clang-format: Don't wrap before the ] of a lambda introducer.

Before:
  return aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa([=
  ](int iiiiiiiiiiii) {
    return aaaaaaaaaaaaaaaaaaaaaaa != aaaaaaaaaaaaaaaaaaaaaaa;
  });

After:
  return aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa([=](
      int iiiiiiiiiiii) {
    return aaaaaaaaaaaaaaaaaaaaaaa != aaaaaaaaaaaaaaaaaaaaaaa;
  });

llvm-svn: 241583