Fixup, Format and Update Markdown files

[Nirmal4G]

Fixes #4068

1. Using MarkdownLint or similar tools, fix and format the markdown files
   • Fix headings
   • Fix anchors in headings
   • Fix dead links (Fixes Dead link in the PR markdown form #4139)
   • Add Code ` quotes to source texts
   • Fix Code snippets with correct file-type tags
   • Fix new lines around headings and paragraphs
2. Replace GitHub emoji identifiers (aka :emoji_id:) with actual emoji symbols

PR Type

What kind of change does this PR introduce?

• Code style update (formatting)
• Documentation content changes

What is the current behavior?

Markdown files have a lot of issues being reported from tools like MarkdownLint. They also use GitHub emoji identifiers.

What is the new behavior?

Fixed and Formatted markdown files with MarkdownLint. Replaced GitHub emoji identifiers with actual emojis.

PR Checklist

Please check if your PR fulfills the following requirements:

• Contains NO breaking changes

Other information

• If you're editing this patch tree, please rebase on latest HEAD and then commit, without updating from the latest HEAD.
• When merging, please update the commit title to PR title instead of the default Merge pull request #xxxx from repo/branch, and commit message to either PR message or messages of individual commits. The auto-merge bot does this by default.

[ghost]

Thanks Nirmal4G for opening a Pull Request! The reviewers will test the PR and highlight if there is any conflict or changes required. If the PR is approved we will proceed to merge the pull request 🙌

[thiago-cs]

I checked the link you fixed and noticed the “readme.md” part of the markdown link to “supported SDKs” was removed. So in order to test it I also removed “readme.md” from the original link target: * Old: https://github.com/CommunityToolkit/WindowsCommunityToolkit/readme.md#supported * New: https://github.com/CommunityToolkit/WindowsCommunityToolkit/#supported The new link points to the Features section of the project’s main page, which can also be accessed through https://github.com/CommunityToolkit/WindowsCommunityToolkit/#-features-mailbox. Seems to me that the issue #4139 is fixed. Should I close it?

[Nirmal4G]

The new link points to the Features section of the project’s main page, which can also be accessed through CommunityToolkit/WindowsCommunityToolkit#-features-mailbox.

That's the old link. The new link will be CommunityToolkit/WindowsCommunityToolkit#-features- when this PR is merged. Use #supported fragment instead of the link fragment that is shown when you hover over the link anchor.

[michael-hawker]

Thanks @Nirmal4G! Think there's a way to add the Markdown Linter tool you used to the CI/Pipeline checks like we do with the header and stylecop formatting?

[Nirmal4G]

@michael-hawker Should be possible, I'm already looking into basic formatting, spelling checks via CI. I'll let you know.