Tonight’s episode of Great Performances on Channel 13 is a backstage look at In the Heights. (Yeah, last year’s Tony winner for Best Musical; these documentaries take time to edit, aparently.) The PBS film contains the customary scenes of actors polishing dance moves and trying out songs in the rehearsal room, but it also focuses on several cast members’ backstories. We learn that the charming Christopher Jackson, who plays Benny, is raising a child with autism. Phenomenal dancer Seth Stewart hints at hardships early in his career. And naturally, there’s tons of disarming and charismatic patter from the show’s Tony-winning composer-lyricist, Lin-Manuel Miranda. Sure, In the Heights: Chasing Broadway Dreams is sort of a feel-good ad for the show, but what it lacks in showbiz dish it makes up for in bighearted vivacity.