SPOILER ALERT: This story discusses major plot points, including the ending for “Saltburn.” Singer-songwriter Sophie Ellis-Bextor was already a fan of Emerald Fennell when she was approached about the use of her 2001 hit “Murder on the Dancefloor” in “Saltburn.” “I loved ‘Promising Young Woman,’” Ellis-Bextor says. But what really sold it to her was the […]