OSTON—Marcel Hug, the men’s wheelchair champion at the 125th Boston Marathon, will now always remember the words that locals recite when discussing the final mile of the race. “Right onto Hereford, left onto Boylston.” Too bad for Hug, he didn’t make that right turn. Instead, he followed the lead vehicle up Commonwealth Avenue before heading back onto Hereford Street. Hug was on a record pace Monday morning and earned $25,000 with his fifth Boston Marathon title. But he lost out on a $50,000 bonus that comes with any course record. The 35-year-old Hug, from Switzerland, wound up finishing in 1 hour, 18 minutes, 11 seconds. He set the course record of 1:18:04 in 2017. “I would say it cost me 20 seconds and it should have been possible to get the record, for sure,” he said. “It should not have happened. It’s my fault,” he said. “I was just focusing …