A Celtics fan was arrested at the TD Garden Sunday night after allegedly throwing a water bottle at Brooklyn Nets’ Kyrie Irving.As Irving walked off the court following Brooklyn’s 141-126 victory over the Celtics, he was nearly hit by a bottle thrown from the stands. Irving and Nets guard Tyler Johnson turned toward the stands and pointed. Police surrounded a man in a Kevin Garnett jersey in the stands before leading him out in handcuffs.Boston police said the man