There are some players you could describe as a ‘scorer of great goals’. One Manchester United player in particular certainly falls into that category. But Roy Keane feels that if he is to reach the next level and go from a very, very good player to a truly world-class one, Marcus Rashford must develop beyond a ‘scorer of great goals’ and into a ‘great goalscorer’ too. You could make quite the compilation of Rashford wondergoals. But while Manchester United’s number ten is famed for cutting in from the left and fizzing trademark shots which threaten to send the net flying onto the M52, the 26-y…