[clang-tools-extra] [clang-tidy][doc][NFC] extract common global options in doc (PR #119842)

[Carlos Galvez via cfe-commits]

carlosgalvezp wrote:

It could also be that `getLocalOrGlobal` was added to keep backwards compatibility and never break users, e.g for an option that used to be local but has become global. But that doesn't mean that that's what we actually want users to do.

https://github.com/llvm/llvm-project/pull/119842