[clang-tools-extra] [clang-tidy] Add `llvm-formatv-string` (PR #195974)

[Zeyi Xu via cfe-commits]

zeyi2 wrote:

> Have you tried running the check over the LLVM codebase? It would be interesting to see if it finds anything.

I'm testing it now, will post the comment here after the run finishes :)

https://github.com/llvm/llvm-project/pull/195974