(This April 18 story refiles to correct identification in paragraph 3 to Climate One radio program from National Public Radio) By Richard Cowan WASHINGTON (Reuters) – Then-President Donald Trump attempted a coup on Jan. 6, 2021, and that will be a centerpiece of committee hearings in Congress next month, said Democrat Jamie Raskin, a committee member who led the prosecution of Trump’s second impeachment. On that day in 2021, Trump supporters stormed the U.S. Capitol building, encouraged by the Republican president in a speech outside the White House to protest formal congressional certificatio…