Every so often, a retro hairstyle comes back in vogue to set the world on fire — and right now, the ‘do du jour is soft, sexy, 1980s ringlets (think Jennifer Beals in “Flashdance,” “A Different World’s” Jasmine Guy, or Whitney circa “I Wanna Dance with Somebody”). Whether it’s about wild spirals, loose ringlets or cute coils, Hollywood’s hottest starlets are turning into girls with curls. Here are our favorites, from Beyonce to Tia Mowry.