From Jimmy Garoppolo seeking his third Super Bowl ring but first as a starting quarterback to Patrick Mahomes trying to join Tom Brady and Ben Roethlisberger as the only QBs in NFL history to win a Super Bowl before his 25th birthday, there are plenty of subplots in the 49ers-Chiefs showdown. Here are some fans should keep an eye on: LIKE FATHER, LIKE SON Kyle Shanahan and his father, Mike, are…