Trench coats, the perfect pair of jeans, a leather motorcycle jacket, a strand of pearls. In fashion, the most versatile items become the most iconic. The same goes for screenwriting. The magic trick of 2006’s “The Devil Wears Prada” was that it contained razor-sharp insights about the worlds of media and celebrity, packaged as a glossy fish-out-of-water story led by Meryl Streep and Anne Hathaway. Aline Brosh McKenna wrote that “sparkling” script, as Streep called it in her Golden Globes