[clang-tools-extra] Update clang tidy Contributing guide (PR #106672)

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MichelleCDjunaidi wrote:

@LegalizeAdulthood Thanks for bringing this up because it slipped my mind to test it on Windows! I honestly have only tested it on Linux, and I currently don't have access to my laptop for the week.

If anyone reads this and tests it out, please tell the results. I'll open a new PR to add the Windows exception if it doesn't work. (Or if there's a better workflow that LLVM uses, do tell.)

https://github.com/llvm/llvm-project/pull/106672