By Daniel Kline The fast-food chain adds something to its menu that may surprise you. Usually when McDonald’s (MCD) – Get McDonald’s Corporation Report innovates it involves bacon, some sort of sauce, or a new take on a fast-food classic. The chain has been a quiet leader in the fast-food space dating back to the 1965 addition of the Filet O’ Fish to its menu. That may not seem like a revolutionary change at the moment but at the time McDonald’s and rival Burger King (not then a Restaurant Brands International (QSR) – Get Restaurant Brands International Inc Report company) had built their menu…