Like countless fans of “ Saturday Night Live ,” I felt like I spent the show’s 50th anniversary year immersed in a tutorial of “SNL” history and its place in show business — I’m talking about all the “SNL50” specials and the anniversary show and Questlove’s music doc and Jason Reitman’s “Saturday Night,” a backstage drama in which almost none of the actors quite nailed the cast members they were playing, yet there was still a vision to the movie, a sense of how “SNL” was the first network