On April 3rd, 2010, a new era of Doctor Who began with “The Eleventh Hour,” and this week, that era came to an end with “Twice Upon a Time,” the Christmas Special that saw Steven Moffat, Peter Capaldi, and a whole host of other creatives from the era take a bow, handing the reigns off to Chris Chibnall and Jodie Whittaker for the show’s next, exciting step forward.