Tennis great Roger Federer, 41, has announced his retirement from the sport following the upcoming Laver Cup. The 20-time grand slam singles champion, seen by many fans as the best men’s tennis player ever, has been out all season after knee surgery but had been expected to bow out in 2023 after having a final cracks at the majors. Federer was due to make his comeback in next week’s Laver Cup in London, a competition he helped dream up, but has now decided it will be his final professional tournament. “The Laver Cup next week in London will be my final ATP event. I will play more tennis in the…