[clang-tools-extra] added option `llvm-header-guard.HeaderDirs` (PR #176940)

[Yanzuo Liu via cfe-commits]

zwuis wrote:

As it is said in https://github.com/llvm/llvm-project/issues/71732#issuecomment-1850372207 , this check is designed only for llvm-project. We will not accept this patch because we don't need this option. But you can

1. Rename this check,
2. Turn everything hard-coded for llvm-project into options,
3. Redirect llvm-header-guard to the new check with specified options (You can refer to cert-dcl16-c).

https://github.com/llvm/llvm-project/pull/176940