Phish’s stunning opener of Fleet Foxes’ “White Winter Hymnal” to kick off their powdered donut night once again bridged the world of jam and indie rock, something we’ve seen with a popular Phish cover–TV On the Radio’s “Golden Age” and to a lesser extent, Apples in Stereo’s “Energy.” Fleet Foxes mastermind Robin Pecknold was unaware of the cover until someone on Instagram mentioned it to…