New York (AFP) – Joni Mitchell delivered her first full set in more than 20 years this weekend, surprising attendees at the Newport Folk Festival alongside country star Brandi Carlile. The show followed Mitchell’s stage cameo earlier this year, when she joined other artists as they performed a moving tribute to her life’s work at the MusiCares pre-Grammy gala. Both moments marked rare public appearances for the trailblazing Mitchell, who in 2015 suffered a brain aneurysm that left her temporarily unable to speak, the aftermath of which has involved extensive physical therapy. Mitchell and Carl…