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

[via cfe-commits]

================
@@ -4,3 +4,11 @@ llvm-header-guard
 =================
 
 Finds and fixes header guards that do not adhere to LLVM style.
+
+Options
+-------
+
+.. option:: HeaderDirs
+
+   A list of directories where the include guard string will start.
+   defaults to `include`.
----------------
EugeneZelenko wrote:

```suggestion
   Defaults value is `include`.
```

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