[clang-tools-extra] [clang-tidy] Rename google-build-namespaces to misc-anonymous-namespace-in-header (PR #173484)

[Baranov Victor via cfe-commits]

vbvictor wrote:

> As the error suggests, line 8 of anonymous-namespace-in-header.rst exceeds 80 char limits (I think this line is exactly 80 chars long?), so is line 9 and line 10 (though these errors are not fired and I'm now sure that this is a bug from doc8.

Will the error fire for lines 9-10 once we fix 8?

https://github.com/llvm/llvm-project/pull/173484