[clang] [clang-format] Separate License text and include blocks (PR #77918)

[via cfe-commits]

================
@@ -171,6 +187,31 @@ void DefinitionBlockSeparator::separateBlocks(
       return false;
     };
 
+    // Separate License text.
----------------
mydeveloperday wrote:

Are we assuming any comment at the top of the file is a license comment? 

https://github.com/llvm/llvm-project/pull/77918