'Do Not Revive' verb for Ghosts (#15934)

* DNR

* Review things

Bound to be something I missed, but testing all seems to work fine.

* Aliven't

code/modules/reagents/chemistry/reagents/medicine.dm

@@ -774,6 +774,11 @@
 				if(M.getBruteLoss() + M.getFireLoss() + M.getCloneLoss() >= 150)
 					M.delayed_gib()
 					return
+				var/mob/dead/observer/ghost = M.get_ghost(TRUE)
+				if(ghost && !ghost.can_reenter_corpse) // DNR or AntagHUD
+					M.visible_message("<span class='warning'>[M] twitches slightly, but is otherwise unresponsive!</span>")
+					return
+
 				if(!M.suiciding && !HAS_TRAIT(M, TRAIT_HUSK) && !HAS_TRAIT(M, TRAIT_BADDNA))
 					var/time_dead = world.time - M.timeofdeath
 					M.visible_message("<span class='warning'>[M] seems to rise from the dead!</span>")