WASHINGTON — Liberal Supreme Court Justice Stephen Breyer is retiring, giving President Joe Biden an opening he has pledged to fill by naming the first Black woman to the high court.Breyer, 83, has been a pragmatic force on a court that has grown increasingly conservative in recent years, trying to forge majorities with more moderate justices right and left of center.Two sources confirmed the news to The Associated Press on Wednesday, speaking on condition of anonymity so as not to preempt Breyer’s formal …