[clang-format] Add .inc extension to git-clang-format

[aganea]

Summary

The .inc extension isn't picked up for formatting when doing git clang-format on the LLVM repo. I'm not sure if we want this at large or more specific just for the LLVM codebase.

clang/tools/clang-format/git-clang-format

else:
     dash_dash = argv[idx:]
     argv = argv[:idx]
 
   default_extensions = ','.join([
       # From clang/lib/Frontend/FrontendOptions.cpp, all lower case
       'c', 'h',  # C
       'm',  # ObjC
       'mm',  # ObjC++
-      'cc', 'cp', 'cpp', 'c++', 'cxx', 'hh', 'hpp', 'hxx',  # C++
+      'cc', 'cp', 'cpp', 'c++', 'cxx', 'hh', 'hpp', 'hxx', 'inc',  # C++
       'ccm', 'cppm', 'cxxm', 'c++m',  # C++ Modules
       'cu', 'cuh',  # CUDA
       # Other languages that clang-format supports
       'proto', 'protodevel',  # Protocol Buffers
       'java',  # Java
       'js',  # JavaScript
       'ts',  # TypeScript
       'cs',  # C Sharp