Tracking missing and broken things

[FelixCCWork]

• Fix nested styles, sub & super (see MarkdownTextBlock: Fix nested styles, sub & super CommunityToolkit/Labs-Windows#614)
• Implement github alert container extension (see https://github.com/xoofx/markdig/blob/master/src/Markdig.Tests/Specs/AlertBlockSpecs.md)
• Add OnMarkdownParsed event (see MarkdownTextBlock: Adds OnMarkdownParsed event CommunityToolkit/Labs-Windows#616)
• Check how to implement extensions ( see [MarkdownTextBlock] Support Extensions CommunityToolkit/Labs-Windows#609)
• Check if we want to add support for code block syntax highlighting #4
  • https://github.com/coltrane2ny/Markdig.Wpf.ColorCode
  • https://github.com/coltrane2ny/ColorCode-WPF
  • https://github.com/CommunityToolkit/ColorCode-Universal

[Felix-CodingClimber]

Moved to separate issues