Anna Wintour today finally confirmed Chioma Nnadi will replace outgoing editor-in-chief Edward Enninful following years of a reported transatlantic power struggle bubbling beneath the surface of the fêted fashion bible. New York-based Londoner Ms Nnadi, currently editor of the US edition's website, will have the title of 'head of editorial content' to focus on 'digital storytelling' and keeping Vogue 'interactive' …