Manchester City are still reaching out for another realm of immortality. Pep Guardiola’s men want to become the first team in Premier League history to win the Treble back to back. And their next five fixtures will bring clarity to that matter. It begins with the visit of Manchester United on Sunday. On Wednesday, they will most definitely wrap up qualification for the Champions League quarter-final when FC Copenhagen are in town. Back in the league, it is leaders Liverpool (A), Newcastle (H), Arsenal (H) and Aston Villa (H). Although Guardiola probably has the fixtures for the rest of the cam…