docs: Adding csharp markup code examples

[eriklimakc]

GitHub Issue: #1302

PR Type

What kind of change does this PR introduce?

• Documentation content changes

Description

PR Checklist

Please check if your PR fulfills the following requirements:

• Commits must be following the Conventional Commits specification
• [ ] Tested the changes where applicable:
  • [ ] UWP
  • [ ] iOS
  • [ ] Android
  • [ ] WASM
  • [ ] MacOS
• [ ] Updated the documentation as needed:
  • [ ] General Doc Update
  • [ ] material-controls-styles.md
  • [ ] cupertino-controls-styles.md
  • [ ] lightweight-styling.md (LightWeight Styling Resource Keys)
• [ ] Contains No breaking changes

  If the pull request contains breaking changes, commit message must contain a detailed description of the action to take for the consumer of this library. As explained by the Conventional Commits specification

Other information

Internal Issue (If applicable):