Japanese gymnast Shinnosuke Oka has swung his way to Olympic gold in an error-strewn horizontal bar event, adding to his team and all-around titles in Paris. The 20-year-old came into the Games as an unknown quantity but leaves as the male gymnast with the most golds from the Bercy Arena – having also taken bronze in the parallel bars earlier. His routine was arguably the easiest of the final but he performed it superbly to prevail on the back of his execution score – having levelled on 14.533 points overall with silver medallist Angel Barajas. It is Colombia’s first ever gymnastics medal. Chi…