Last year, Taylor Swift counted herself among the "tortured poets," but nowadays she is a self-described "showgirl," having released a short album full of bite-size songs co-produced by the distinguished hitmakers Max Martin and Shellback. The year's biggest new musical act is probably Huntr/x, the fictional girl group from the animated Netflix film "KPop Demon Hunters." When Demi Lovato, the former Disney teen idol, wanted to go back to her roots, she released "Fast," a perfectly superficial club track;