clang-format: Make formatting of member function reference qualifiers

more consistent.

Before:
  SomeType MemberFunction(const Deleted &)&&;
  SomeType MemberFunction(const Deleted &) && { ... }

After:
  SomeType MemberFunction(const Deleted &)&&;
  SomeType MemberFunction(const Deleted &)&& { ... }

llvm-svn: 245843