“Stay busy with beauty as well as outrage.” That’s how Anaïs Mitchell answered a question I posed to her recently about the power of song to nurture social change. “I remember going to demonstrations when I was young and noticing how expressions of beauty spoke just as loudly as expressions of outrage,” Mitchell said. “Both are valid, but music and art have a way of saying ‘Listen, look, it could be like this instead!’ That’s been a life lesson …