[git-clang-format] Process CUDA header files

[tomilov]

Summary

Clang supports compiling CUDA source files,
CUDA header files may contain CUDA specific code
that is why they have special extension, which
can be recognized by nvcc (CUDA compiler driver)
as CUDA source file.
Format them by default as well.

[MyDeveloperDay]

LGTM

[tomilov]

@MyDeveloperDay May you commit it on my behalf, please? I have no rights to land it properly.

[MyDeveloperDay]

I'm happy to do this in time, but let's wait a little in case others have any comments

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

else:
     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++
-      'cu',  # CUDA
+      'cu', 'cuh',  # CUDA
       # Other languages that clang-format supports
       'proto', 'protodevel',  # Protocol Buffers
       'java',  # Java
       'js',  # JavaScript
       'ts',  # TypeScript
       'cs',  # C Sharp
       ])