[clang-tools-extra] Allow to pass config file to clang-tidy-diff (PR #75457)

[Chris Apple via cfe-commits]

cjappl wrote:

@MichaelLettrich I just realized I submitted basically the same PR as you! Great minds think alike. I found yours when I searched.

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

In this PR I added to the release notes, feel free to steal them if you want. I would love this feature in `main`

https://github.com/llvm/llvm-project/pull/75457