“We’re the Highwomen, sing a story still untold,” sang Brandi Carlile, Maren Morris, Amanda Shires and Natalie Hemby at their first-ever performance as the Highwomen Friday evening at the Newport Folk Festival. The supergroup was also backed by a band that included Jason Isbell and the Hanseroth Twins during the hourlong set. “This is our first show y’all, and we’re fucking terrified,” Carlile told the crowd early on. But the band’s debut ...