[clang] [clang-tools-extra] [clang] Extend diagnose_if to accept more detailed warning information (PR #70976)

[Nikolas Klauser via cfe-commits]

philnik777 wrote:

@AaronBallman @erichkeane is there anything else to do before merging? It would be nice to merge this somewhat early in the release cycle, since I suspect this might be reverted a few times.

https://github.com/llvm/llvm-project/pull/70976