gh-292: Add markdownlint to list of pre-commit hooks (#295)

Closes #292. Adds `markdownlint` as another `pre-commit` hook. I have
used this one extensively
https://github.com/igorshubovych/markdownlint-cli.

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

.pre-commit-config.yaml

@@ -51,3 +51,9 @@ repos:
     rev: v3.3.3
     hooks:
       - id: prettier
+  - repo: https://github.com/igorshubovych/markdownlint-cli
+    rev: v0.41.0
+    hooks:
+      - id: markdownlint-fix
+        args:
+          - --dot

CHANGELOG.md

@@ -1,3 +1,5 @@
+<!-- markdownlint-disable MD024 -->
+
 # Changelog
 
 All notable changes to the project are documented in this file. The format is

CODE_OF_CONDUCT.md

@@ -23,7 +23,7 @@ community include:
 - Accepting responsibility and apologising to those affected by our mistakes,
   and learning from the experience
 
-* Focusing on what is best not just for us as individuals, but for the overall
+- Focusing on what is best not just for us as individuals, but for the overall
   community
 
 Examples of unacceptable behaviour include:
@@ -116,13 +116,13 @@ community.
 
 This Code of Conduct is adapted from the [Contributor Covenant][homepage],
 version 2.0, available at
-https://www.contributor-covenant.org/version/2/0/code_of_conduct.html.
+<https://www.contributor-covenant.org/version/2/0/code_of_conduct.html>.
 
 Community Impact Guidelines were inspired by
 [Mozilla's code of conduct enforcement ladder](https://github.com/mozilla/diversity).
 
 [homepage]: https://www.contributor-covenant.org
 
 For answers to common questions about this code of conduct, see the FAQ at
-https://www.contributor-covenant.org/faq. Translations are available at
-https://www.contributor-covenant.org/translations.
+<https://www.contributor-covenant.org/faq>. Translations are available at
+<https://www.contributor-covenant.org/translations>.

CONTRIBUTING.md

@@ -201,7 +201,9 @@ to which the pull request refers.
 
 Pull requests to the `main` branch should have titles of the following form:
 
-    gh-<issue-number>: Subject line
+```markdown
+gh-<issue-number>: Subject line
+```
 
 The body of the pull request should contain a description of the changes, and
 any relevant details or caveats of the implementation.
@@ -214,25 +216,34 @@ request description, separated from the message body by a blank line.
 To generically refer to an issue without any further action, use `Refs` and one
 or more GitHub issue numbers:
 
-    Refs: #12
-    Refs: #25, #65
+```markdown
+Refs: #12
+
+Refs: #25, #65
+```
 
 To indicate that the pull request shall close an open issue, use `Closes` and a
 single GitHub issue number:
 
-    Closes: #17
+```markdown
+Closes: #17
+```
 
 Changelog entries are collected using the following trailers, and later parsed
 into the [changelog](CHANGELOG.md) for the next release:
 
-    Added: Some new feature
-    Changed: Some change in existing functionality
-    Deprecated: Some soon-to-be removed feature
-    Removed: Some now removed feature
-    Fixed: Some bug fix
-    Security: Some vulnerability was fixed
+```Text
+Added: Some new feature
+Changed: Some change in existing functionality
+Deprecated: Some soon-to-be removed feature
+Removed: Some now removed feature
+Fixed: Some bug fix
+Security: Some vulnerability was fixed
+```
 
 You can use any of the other common git trailers. In particular, you can use
 `Cc` to notify others of your pull request via their GitHub user names:
 
-    Cc: @octocat
+```markdown
+Cc: @octocat
+```