[clang-tools-extra] [clang-tidy] Add an option to treat warnings as errors (PR #128221)

[Carlos Galvez via cfe-commits]

carlosgalvezp wrote:

Nit: specific in the commit message title that this is about clang-tidy-diff.py. Otherwise it seems you are adding warnings as errors to clang-tidy itself.

https://github.com/llvm/llvm-project/pull/128221