There are Taylor Swift songs that lodge themselves eternally in your head after just one listen; there are others whose lyrics are destined to be quoted among fans and shouted back at concerts for perpetuity. But “Carolina,” her understated contribution to the upcoming film Where the Crawdads Sing, seems to have been written with one specific purpose: to set the scene. Swift sings about creeks and back roads, mist and clouds, mud and pines. Working once again with producer Aaron Dessner, she favors acoustic instruments and minor chords that conjure the same haunted, naturalistic imagery.