By Jan Wolfe and Jacqueline Thomsen WASHINGTON (Reuters) – A leader of the far-right Proud Boys pleaded guilty on Friday to charges related to the attack on the U.S. Capitol, a victory for prosecutors that could bolster their cases against members of the group. Charles Donohoe, the leader of the group’s North Carolina chapter at the time of the Capitol attack, entered the guilty plea during court hearing on Friday in the District of Columbia. Donohoe admitted to conspiracy to obstruct an official proceeding, and assaulting and impeding police officers. Under U.S. sentencing guidelines, Donohoe…