clang-format: Fix overloaded operator edge case.

Before:
  template <class F>
  void Call(F f) {
    f.template operator() <int>();
  }

After:
  template <class F>
  void Call(F f) {
    f.template operator()<int>();
  }

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@220202 91177308-0d34-0410-b5e6-96231b3b80d8