Not hitting much lately? Grab a Snitker. You’re not you when you’re slumping and Mets fans know that better than anyone. After too many nights of runners stranded and warning-track fly balls, this lineup has been hungry for something or someone to finally satisfy. Enter Troy Snitker, the new Mets hitting coach, here to feed an offense that’s been living off empty calories. He’s not a candy bar, though his last name sounds like one. He’s a data-loving, launch-angle-tracking