ManchesterFA Cup final.The Manchester City boss is too focussed on the job in hand, which is the semi-final against Arsenal, to consider the possibility of a piece of football history.The nearest City and Manchester United have come to a final was when they met in the 2011 semi-final at Wembley, when Yaya Toure’s goal sent them into the final, where they ended a 35-year trophy drought with victory over Stoke.But United face Chelsea on Sunday, the day after the Blues take on the Gunners.Sadly, if