In one of his final shows before The Late Show ends on May 21, Colbert opened by noting he had only five episodes remaining. He then pivoted to criticism of CBS News anchor Tony Dokoupil, who failed to secure a visa to cover President Trump's summit with Chinese President Xi Jinping in Beijing.According to The Daily Beast reporting, Dokoupil was forced to cover the historic event from Taipei, Taiwan—over 1,000 miles away—while his competitors at…