[clang-tools-extra] [clangd] Improve Markup Rendering (PR #140498)

[Maksim Ivanov via cfe-commits]

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@@ -118,8 +138,8 @@ class Document {
   BulletList &addBulletList();
 
   /// Doesn't contain any trailing newlines.
-  /// We try to make the markdown human-readable, e.g. avoid extra escaping.
-  /// At least one client (coc.nvim) displays the markdown verbatim!
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emaxx-google wrote:

This deleted comment refers to `coc.nvim`s rendering of markdown - would this PR cause a change of behavior for that use case? If I understand correctly, the prior work intentionally targeted clients, like this, with limited markdown rendering support.

If that's the case and we somehow need to find a balance between Markdown capabilities of different clients, could the `MarkdownClientCapabilities` flags be used to guard the necessary logic?

https://github.com/llvm/llvm-project/pull/140498