[clang] [clang][analyzer][doc] Migrate user-related docs from HTML to RST (PR #97034)

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gamesh411 wrote:

Some parts, especially Apple-related sections, may no longer be relevant in the docs.
Please share insights into which parts should be corrected or omitted from the migration process.
The legacy Clang builds (the most recent one uses Clang version 4.0.0) are still on the clang-analyzer.llvm.org site, and this seems to be the only part that requires the HTML page and the hosting provider (AFAIK).

https://github.com/llvm/llvm-project/pull/97034