Selena Gomez is reminding me exactly why a simple red nail can never be beat. On May 6, Gomez supported her Only Murders in the Building co-star, Martin Short, at the Los Angeles premiere of his new Netflix documentary, Marty, Life Is Short . She showed up wearing an all-black, cap-sleeve Carolina Herrera midi dress that was embellished with teardrop crystals. She wore black, patent leather pumps on her feet and kept her glam relatively simple by pulling her hair back into a sleek bun , but she added a tiny pop of color to her look via her manicure. After wearing nude nail colors during a handful of her most recent public appearances, Gomez appears to be summoning summer with bold, red lipstick and a matching red manicure . Over on Instagram, Gomez's longtime manicurist, Tom Bachik, shared a close-up photo of the singer's nails from the night to his feed.…