[RFC] Implementing reveal highlight

[Losses]

Feature Request

Reveal highlight makes fluent design system attractive and unique, many developers tried to implement it and some possible implementation appears recent years.

Our team made one several month ago, with canvas, which provided acceptable (and the best) performance and visual effects.

We've proved it's possible to have one, and it would be great if the official version of fluent design system implementation could have reveal highlight.

Here are the record:

Detailed document of our implementation: https://ax-design.github.io/demo/reveal-highlight.html
The GitHub Repo: https://github.com/ax-design/reveal-highlight

Please notice that our implementation is based on Web Components, you may need to open some flag on your browser to make it work, a React implement was made before but archived.