[clang-tools-extra] Add ability to pass in a clang-tidy config file to clang-tidy-diff (PR #75721)

[Chris Apple via cfe-commits]

cjappl wrote:

This is almost exactly the same as #75457 , just with the release notes. I'm going to close this for now and re-open it if that one gets stale.

https://github.com/llvm/llvm-project/pull/75721