(Removes reference to Tiffanie Harrison being the first Black woman elected to the Round Rock school board) By James Oliphant ROUND ROCK, Texas -At traffic-choked intersections in this Texas town, a blunt campaign slogan stands out from clusters of candidate signs: “Teach ABCs + 123s, Not CRTs & LGBTs.” Blood-sport politics have come to school board elections in Round Rock, a rapidly growing and diversifying suburb of Austin. Parents are forming political action committees, canvassing door-to-door and sparring on social media. National interest groups, political parties and unions are weighing…