LONDON (Reuters) - Rapper Jay-Z has reached the top of the British album charts for the first time with his new release "Magna Carta...Holy Grail", sales figures showed on Sunday. The hip hop artist knocked the English folk rock band Mumford & Sons off the number one spot, according to the Official Charts Company, which compiles the weekly rundown. Jay-Z's new album features guest appearances by his wife Beyonce and singer Justin Timberlake. Seven of his previous albums have entered the British top 40, but none had reached the number one position, the compiler said. ...