(Reuters) – Neil Warnock announced his retirement from football on Saturday at the age of 73, bringing the curtain down on a record-breaking career spanning more than four decades. Warnock, a former winger who started his managerial career in 1980, last managed second-tier club Middlesbrough before leaving the Championship side by mutual consent in November. The veteran managed sides in 1,603 games and achieved promotion eight times in his career – both marking records in English professional football. He also shares the record for most promotions to the top flight (four) and managed 14 differ…