Replace super weird "locate(/obj/item/weapon/grab, locate(/obj/item/weapon/grab, mob.grabbed_by.len))" by simple if(grabbed_by.len)"
Cleans up Process_Grab to be easier to read.
Simplifies MobBump() proc, especially the part about pushing a mob that is pulling or is pullsed/grabbed. We no longer check for mobs in a 1 tile radius every time we bump a mob.
Fixes runtime with clear_reagents_to_vomit_pool() due to a typo.