In Season 2 of “The Cosby Show,” there’s an episode titled “Happy Anniversary” wherein the entire Huxtable family gathers in front of their living room staircase to perform a lip-synced version of the slinky rhythm and blues classic “Night Time is the Right Time.” It’s an exuberant moment, created to celebrate the wedding anniversary of Dr. Huxtable’s parents, and it is full of love and style and joy. And it’s funny. In his new four-part docuseries “We Need to Talk About Cosby” (premiering Sunday on Showtime), director W. Kamau Bell shows this clip to a number of people he interviews, includin…
