[clang-tools-extra] Add option to exclude headers from clang-tidy analysis (PR #91400)

[Carlos Galvez via cfe-commits]

carlosgalvezp wrote:

>  It seems to be running on my .h files itself(?)

In that case, I don't believe clang-tidy considers the header "a header", but actually "the main file" just like when analyzing a .cpp file. In that case, `ExcludeHeaderFilterRegex` won't work.

https://github.com/llvm/llvm-project/pull/91400