Add support for markdown -> XAML parsing (#17585)

This adds support to the Terminal for parsing Markdown to XAML. We're
using https://github.com/github/cmark-gfm as our parser, so that we can
support the fullness of github-flavored markdown.

The parser parses the markdown to produce a `RichTextBlock`, which
covers just about all the scenarios we need. Since we're initially just
targeting using this for "Release notes", I didn't implement
_everything_ in markdown[^1]. But headers, bold & italic, unordered
lists, images, links, code spans & blocks - all that works. We can work
on additional elements as we need them. The parser is encapsulated into
`Microsoft.Terminal.UI.Markdown.dll`, so that we won't load it on
startup, only when the pane is actually made the first time.

To test this out, I've added a `MarkdownPaneContent` pane type on
`x-markdown` (the `x-` is "experimental"). Go ahead and add that with:

```json
{ "command": { "action": "splitPane", "type": "x-markdown" } }
```

That's got the ability to load arbitrary MD files and render them. I
wouldn't call that experience finished though[^2][^3](and it probably
won't be in 1.22 timeframe). However, it is an excellent testbed for
validating what we do and do not support.

We'll use the markdown parser Soon<sup>TM</sup> for the What's New
panes.

* Done in pursuit of displaying release notes in the Terminal.
* Doesn't quite close out #16495 
* Should make #8647 possible
* may help with #16484

[^1]: the most notable gap being "block quotes" with `>`. I don't think
I can draw a vertical line in a rich text block easily. Footnotes are
also missing, as well as tables.
[^2]: I say it's not finished because the aforementioned MD gaps. Also
the UX there is not polished at all.
[^3]: I don't believe we'll have time to polish out the pure markdown
pane for 1.22, but what the parser covers now is more than enough for
the release notes pane in time for 1.22

.github/actions/spelling/allow/allow.txt

@@ -5,6 +5,7 @@ breadcrumbs
 ccmp
 ccon
 clickable
+cmark
 CMMI
 colorbrewer
 consvc
@@ -22,6 +23,7 @@ Emacspeak
 Fitt
 FTCS
 gantt
+gfm
 ghe
 gje
 godbolt

.github/actions/spelling/allow/apis.txt

@@ -43,6 +43,7 @@ DONTADDTORECENT
 DWMSBT
 DWMWA
 DWORDLONG
+EMPH
 endfor
 ENDSESSION
 enumset
@@ -62,6 +63,7 @@ GETDESKWALLPAPER
 GETHIGHCONTRAST
 GETMOUSEHOVERTIME
 GETTEXTLENGTH
+HARDBREAKS
 Hashtable
 HIGHCONTRASTON
 HIGHCONTRASTW
@@ -115,6 +117,7 @@ IUri
 IVirtual
 KEYSELECT
 LCID
+LINEBREAK
 llabs
 llu
 localtime
@@ -148,6 +151,7 @@ NIF
 NIN
 NOAGGREGATION
 NOASYNC
+NOBREAKS
 NOCHANGEDIR
 NOPROGRESS
 NOREDIRECTIONBITMAP
@@ -204,6 +208,7 @@ SINGLEUSE
 SIZENS
 smoothstep
 snprintf
+SOFTBREAK
 spsc
 sregex
 SRWLOC

.github/actions/spelling/excludes.txt

@@ -104,6 +104,7 @@
 ^doc/reference/UTF8-torture-test\.txt$
 ^doc/reference/windows-terminal-logo\.ans$
 ^oss/
+^NOTICE.md
 ^samples/PixelShaders/Screenshots/
 ^src/interactivity/onecore/BgfxEngine\.
 ^src/renderer/atlas/

NOTICE.md

@@ -281,6 +281,181 @@ CONDITIONS OF ANY KIND, either express or implied. See the License for the
 specific language governing permissions and limitations under the License.
 ```
 
+## cmark
+**Source**: [https://github.com/commonmark/cmark](https://github.com/commonmark/cmark)
+
+### License
+Copyright (c) 2014, John MacFarlane
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+-----
+
+houdini.h, houdini_href_e.c, houdini_html_e.c, houdini_html_u.c
+
+derive from https://github.com/vmg/houdini (with some modifications)
+
+Copyright (C) 2012 Vicent Martí
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
+-----
+
+buffer.h, buffer.c, chunk.h
+
+are derived from code (C) 2012 Github, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
+-----
+
+utf8.c and utf8.c
+
+are derived from utf8proc
+(<http://www.public-software-group.org/utf8proc>),
+(C) 2009 Public Software Group e. V., Berlin, Germany.
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+
+-----
+
+The normalization code in normalize.py was derived from the
+markdowntest project, Copyright 2013 Karl Dubost:
+
+The MIT License (MIT)
+
+Copyright (c) 2013 Karl Dubost
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+-----
+
+The CommonMark spec (test/spec.txt) is
+
+Copyright (C) 2014-15 John MacFarlane
+
+Released under the Creative Commons CC-BY-SA 4.0 license:
+<http://creativecommons.org/licenses/by-sa/4.0/>.
+
+-----
+
+The test software in test/ is
+
+Copyright (c) 2014, John MacFarlane
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
 # Microsoft Open Source
 
 This product also incorporates source code from other Microsoft open source projects, all licensed under the MIT license.

OpenConsole.sln

@@ -405,6 +405,8 @@ Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "RenderingTests", "src\tools
 EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "Microsoft.Terminal.UI", "src\cascadia\UIHelpers\UIHelpers.vcxproj", "{6515F03F-E56D-4DB4-B23D-AC4FB80DB36F}"
 EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "Microsoft.Terminal.UI.Markdown", "src\cascadia\UIMarkdown\UIMarkdown.vcxproj", "{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}"
+EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "benchcat", "src\tools\benchcat\benchcat.vcxproj", "{2C836962-9543-4CE5-B834-D28E1F124B66}"
 EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "ConsoleMonitor", "src\tools\ConsoleMonitor\ConsoleMonitor.vcxproj", "{328729E9-6723-416E-9C98-951F1473BBE1}"
@@ -2302,6 +2304,28 @@ Global
 		{6515F03F-E56D-4DB4-B23D-AC4FB80DB36F}.Release|x64.Build.0 = Release|x64
 		{6515F03F-E56D-4DB4-B23D-AC4FB80DB36F}.Release|x86.ActiveCfg = Release|Win32
 		{6515F03F-E56D-4DB4-B23D-AC4FB80DB36F}.Release|x86.Build.0 = Release|Win32
+        {7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.AuditMode|Any CPU.ActiveCfg = Debug|Win32
+        {7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.AuditMode|ARM64.ActiveCfg = Release|ARM64
+        {7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.AuditMode|x64.ActiveCfg = Release|x64
+        {7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.AuditMode|x86.ActiveCfg = Release|Win32
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.Debug|Any CPU.ActiveCfg = Debug|x64
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.Debug|ARM64.ActiveCfg = Debug|ARM64
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.Debug|ARM64.Build.0 = Debug|ARM64
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.Debug|x64.ActiveCfg = Debug|x64
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.Debug|x64.Build.0 = Debug|x64
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.Debug|x86.ActiveCfg = Debug|Win32
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.Debug|x86.Build.0 = Debug|Win32
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.Fuzzing|Any CPU.ActiveCfg = Fuzzing|x64
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.Fuzzing|ARM64.ActiveCfg = Fuzzing|ARM64
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.Fuzzing|x64.ActiveCfg = Fuzzing|x64
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.Fuzzing|x86.ActiveCfg = Fuzzing|Win32
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.Release|Any CPU.ActiveCfg = Release|x64
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.Release|ARM64.ActiveCfg = Release|ARM64
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.Release|ARM64.Build.0 = Release|ARM64
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.Release|x64.ActiveCfg = Release|x64
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.Release|x64.Build.0 = Release|x64
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.Release|x86.ActiveCfg = Release|Win32
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F}.Release|x86.Build.0 = Release|Win32
 		{2C836962-9543-4CE5-B834-D28E1F124B66}.AuditMode|Any CPU.ActiveCfg = AuditMode|Win32
 		{2C836962-9543-4CE5-B834-D28E1F124B66}.AuditMode|ARM64.ActiveCfg = Release|ARM64
 		{2C836962-9543-4CE5-B834-D28E1F124B66}.AuditMode|x64.ActiveCfg = Release|x64
@@ -2455,6 +2479,7 @@ Global
 		{613CCB57-5FA9-48EF-80D0-6B1E319E20C4} = {A10C4720-DCA4-4640-9749-67F4314F527C}
 		{37C995E0-2349-4154-8E77-4A52C0C7F46D} = {A10C4720-DCA4-4640-9749-67F4314F527C}
 		{6515F03F-E56D-4DB4-B23D-AC4FB80DB36F} = {61901E80-E97D-4D61-A9BB-E8F2FDA8B40C}
+		{7615F03F-E56D-4DB4-B23D-BD4FB80DB36F} = {61901E80-E97D-4D61-A9BB-E8F2FDA8B40C}
 		{2C836962-9543-4CE5-B834-D28E1F124B66} = {A10C4720-DCA4-4640-9749-67F4314F527C}
 		{328729E9-6723-416E-9C98-951F1473BBE1} = {A10C4720-DCA4-4640-9749-67F4314F527C}
 		{BE92101C-04F8-48DA-99F0-E1F4F1D2DC48} = {A10C4720-DCA4-4640-9749-67F4314F527C}