clang-format: [ObjC] Fix using selector names as macro arguments.

Before:
  [self aaaaa:MACRO(a, b :, c :)];

After:
  [self aaaaa:MACRO(a, b:, c:)];

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@220197 91177308-0d34-0410-b5e6-96231b3b80d8