clang-format: Add proto files and JavaScript to git-clang-format.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@205842 91177308-0d34-0410-b5e6-96231b3b80d8
clang-format: Recognize lists ending in trailing commas correctly.

Previously, this did not look through trailing comments leading to a few
formatting oddities.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@205843 91177308-0d34-0410-b5e6-96231b3b80d8