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

[Endre Fülöp via cfe-commits]

gamesh411 wrote:

* Updated the HTML pages to use the redirect logic in available_checks.html (instead of deleting them).
* Updated the usages of 'the static analyzer' in the files touched by this patch.
@steakhal, @NagyDonat, @haoNoQ Thanks for the snappy review!

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