(Reuters) -Britain’s most decorated Olympian Jason Kenny has called time on his cycling career and will take up a position as a sprint coach with British Cycling, the 33-year-old said. Kenny became Britain’s greatest Olympian as he powered to victory in the men’s keirin at the Tokyo Games in August to win the seventh gold medal of his incredible career and surpass former track cycling team mate Chris Hoy. Kenny’s nine Olympic medals is the most by a British athlete in any sport and he had said in November he was not optimistic about competing in Paris 2024 due to pain while training. “A massiv…