By Jennifer Piacenti Second-year QB may be ready to take the next step, but the Patriots don’t have many weapons around him. Patriots head coach Bill Belichick praised Mac Jones’s “dramatic improvement” Tuesday morning, the day before New England’s first official practice of training camp. Belichick, not known to be effusive with praise, commended Jones’s “physical work and conditioning, mechanics, footwork, understanding of our offense (and) opponent defenses.” Perhaps most importantly, Belichick praised the mental aspect of his quarterback’s game, saying, “he’s starting from a much, much hig…