Update file encoding to UTF-8 with BOM (#8099)

Since integrating our repos, there have been a number of changes in PRs that touch the encoding of the file, adding or removing a BOM as the editor in question decides. I've standardized on UTF-8 with BOM, as we do in roslyn, and put it in the .gitattributes so it should hopefully stay consistent.

Author: 333fred

.devcontainer/Dockerfile

@@ -1,4 +1,4 @@
-# See here for image contents: https://github.com/microsoft/vscode-dev-containers/tree/v0.154.0/containers/dotnet/.devcontainer/base.Dockerfile
+# See here for image contents: https://github.com/microsoft/vscode-dev-containers/tree/v0.154.0/containers/dotnet/.devcontainer/base.Dockerfile
 
 # [Choice] .NET version: 5.0, 3.1, 2.1
 ARG VARIANT="5.0"

.editorconfig

@@ -1,4 +1,4 @@
-# EditorConfig is awesome:http://EditorConfig.org
+# EditorConfig is awesome:http://EditorConfig.org
 
 # top-most EditorConfig file
 root = true

.gitattributes

@@ -1,4 +1,4 @@
-* text=auto
+* text=auto
 
 # Collapse these files in PRs by default
 *.xlf linguist-generated=true

.github/CODEOWNERS

@@ -1,4 +1,4 @@
-# Users referenced in this file will automatically be requested as reviewers for PRs that modify the given paths.
+# Users referenced in this file will automatically be requested as reviewers for PRs that modify the given paths.
 # See https://help.github.com/articles/about-code-owners/
 
 /global.json                                   @dotnet/razor-tooling @dotnet/razor-compiler

.github/ISSUE_TEMPLATE/bug_report.md

@@ -1 +1 @@
-blank_issues_enabled: true
+blank_issues_enabled: true

.github/ISSUE_TEMPLATE/config.yml

@@ -1,4 +1,4 @@
-syntax: glob
+syntax: glob
 
 ### VisualStudio ###
 

.github/ISSUE_TEMPLATE/feature_request.md

@@ -1,4 +1,4 @@
-{
+{
   "version": "1.0",
   "components": [
     "Microsoft.Net.Component.4.6.2.TargetingPack",