You might not have noticed, but President Biden is trying to overhaul the student loan system. Even as his controversial student debt forgiveness scheme heads to the Supreme Court, the Education Department is advancing another audacious plan to reshape how higher-education loans work — and not just for existing borrowers, but future ones, too. This means it could soon redefine the nation’s higher-education loan system, which some 70 percent of college students use to finance their degrees.