WASHINGTON — Newly opened records that belonged to Supreme Court Justice John Paul Stevens give the public a behind-the-scenes glimpse at his decades on the court, including the tense struggle over the 2000 presidential election and major cases on affirmative action and abortion.Documents that became available Tuesday show the justices’ strong, personal reactions as they considered Bush v. Gore, with conservatives complaining about the tone of their liberal colleagues’ writings.They also show Stevens …