[clang] [clang-tools-extra] [llvm] [clang] Introduce diagnostics suppression mappings (PR #112517)

[kadir çetinkaya via cfe-commits]

kadircet wrote:

> clang/docs/ReleaseNotes.rst?

I was planning to add docs in a follow up once the UX is more mature, but I guess it doesn't hurt to do that here as well.

https://github.com/llvm/llvm-project/pull/112517