Ben Marshall, a writer on “Saturday Night Live” and member of the comedy trio Please Don’t Destroy, is joining the cast along with four other newcomers for Season 51. After a landmark 50th season — complete with multiple celebratory events and a slew of Emmy nominations — “Saturday Night Live” is ready for some changes. NBC announced Tuesday that five new cast members would be joining the storied series for the upcoming 51st season aftera handful of individual cast members shared that they wouldnot be returning. It’s unclear if additional departures will be announced, but creator and producer Lorne Michaels…