[clang] [clang][analyzer][doc] Migrate checkers-related docs from HTML to RST (PR #97032)

[Endre Fülöp via cfe-commits]

gamesh411 wrote:

I have tried to ensure no information is lost with this change.
I have cross-checked the history of the checker's HTML files with commits that introduce checkers and have found that we tend to add checkers only to the RST files and sometimes miss the fact that there is another description in the HTML format.

https://github.com/llvm/llvm-project/pull/97032