While working on documenting APIs of a rust crate, I found that it would be nice to have a live rendered view of current editing function / struct documentation in a separate window in my editor.
I think it is not so hard to implement, it would be similar to how we implement Show Syntax Tree and could be possible to reuse some hover code for that.
I have even one more feature that I really miss from TypeScript. This is highlighting markdown syntax in doc comments:

Anyway, rendering live markdown preview is kinda doable, this just needs vscode API investigation.
What about full language support in markdown code blocks? Is there an issue for that? Granted, it may not necessarily be a rust-specific solution. See this intention:
https://github.com/pushqrdx/code-fences#planned
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I have even one more feature that I really miss from TypeScript. This is highlighting markdown syntax in doc comments:

Anyway, rendering live markdown preview is kinda doable, this just needs vscode API investigation.