Midsommar probably won't encourage folks to book tickets for a Swedish vacation anytime soon. What Ari Aster's new folk-horror film might do, however, is spark some curiosity as to the film's mythology and just how far it deviates from reality. The story centers on a group of Americans who travel to the Swedish hinterland at the invitation of their university friend in order to participate in a once-in-a-lifetime spring festival. What happens once they're there is something that's lost to legend and fiercely protected by the locals, but luckily we get …