clang-format: Fix formatting of class template declaration.

Before:
  template <class R, class C>
  struct Aaaaaaaaaaaaaaaaa<R (C::*)(int)
                           const> : Aaaaaaaaaaaaaaaaa<R (C::*)(int)> {};

After:
  template <class R, class C>
  struct Aaaaaaaaaaaaaaaaa<R (C::*)(int) const>
      : Aaaaaaaaaaaaaaaaa<R (C::*)(int)> {};