clang-format-diff.py: add the OpenCL file extension

It's handled correctly as a C-family language.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@197542 91177308-0d34-0410-b5e6-96231b3b80d8
Fix comment-code function name mismatch

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@197544 91177308-0d34-0410-b5e6-96231b3b80d8