Alison Ellwood’s “Let the Canary Sing,” a documentary examining the life and career of 80s pop star Cyndi Lauper, risks being unremarkable if not for its subject's distinctive nature. Lauper is widely recognized for her unusual style and memorable songs like "She Bop," "Money Changes Everything," and "Time After Time.” The film highlights a less familiar side of the performer—her personal life and activism. It’s r…