[llvm-branch-commits] [clang-tidy] Add FixIts for libc namespace macros (PR #99681)

[Paul Kirth via llvm-branch-commits]

https://github.com/ilovepi created https://github.com/llvm/llvm-project/pull/99681

This adds a few FixIts that update the usage of namespaces other than
LIBC_NAMESPACE_DECL, and add the required header when its missing.