President-elect Donald J. Trump on Tuesday tapped Linda McMahon, a former professional wrestling executive who ran the Small Business Administration for much of his first term, to lead the Education Department, an agency he has routinely singled out for elimination in his upcoming term. A close friend of Mr. Trump’s and a longtime booster of his political career, Ms. McMahon had been among his early donors leading up to his electoral victory in 2016 and has been one of the leaders of...