Finally, here’s an “Into the Woods” trailer with singing. Lots of singing, in fact! Meryl Streep sings the most (her highlight is “Stay With Me” at the trailer’s end), but music sprouts up all over the place. This is a musical. Directed by Rob Marshall (“Chicago”), “Into the Woods” is out in theaters on Christmas Day; Streep’s the Witch, Johnny Depp’s the Wolf, Anna Kendrick is Cinderella, Chris Pine is the Prince, James Corden is the Baker and Emily Blunt is the Baker’s Wife.