PG-13 | 1h 28m | Documentary | March 8, 2014 Liam Neeson, former heavyweight amateur boxer-turned-actor, narrates “Manny,” a powerful, if somewhat superficial, documentary about legend-in-his-own-time Filipino boxer Manuel “Pacman” Pacquiao. Manny Pacquiao (center) winning a belt in “Manny.” (Gravitas Ventures/Universal Pictures) Pacquiao was the only boxer in history to win championships across eight different weight classes. He’s a…