The White House Correspondents’ Dinner has had multiple iterations since it began a few years after World War I. Washington’s premier soiree on Saturday is most identified by its modern form: a red carpet for the capital’s journalism elite, political staffers and an assortment of American business leaders and celebrities — with the leader of the free world and a comedian offering roasts. Some years are forgettable and relegated to C-SPAN archives. Others produce viral moments — funny,