SAG-AFTRA issued a memorable one-liner Thursday when Donald Trump resigned from the Hollywood actors union ahead of a disciplinary hearing. “Thank you,” it said in a startlingly short, two-word statement. The caustic comeback followed after Trump sent a petulant letter Thursday “revoking” his union membership. “I write to you today regarding the so-called Disciplinary Committee hearing aimed at revoking my union membership. Who cares!” Trump wrote in the letter apparently signed with a fat black marker. “While I’m not familiar with your work, I’m very proud of my work on movies such as Home Al...