FORT WORTH, Texas — PGA Tour golfers pinned maroon ribbons to their hats and a few wrote “L L L L” on their gloves and shoes to honor the victims of the Uvalde school shooting during the opening round of the Charles Schwab Challenge on Thursday in Fort Worth. The four Ls are a nod to Robb Elementary School’s student mission statement of “Live. Learn. Love. Lead.” A gunman killed 19 children and two teachers at the school on Tuesday. “Anytime you see stuff like that, I can’t imagine what those families are going through right now,” said Scottie Scheffler, the world’s top-ranked golfer who calls…