'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/mob/dead/observer/observer.dm

@@ -387,6 +387,30 @@ This is the proc mobs get to turn into a ghost. Forked from ghostize due to comp
 		to_chat(usr, "AntagHud Toggled OFF")
 		M.antagHUD = FALSE
 
+/mob/dead/observer/verb/set_dnr()
+	set name = "Set DNR"
+	set category = "Ghost"
+	set desc = "Prevent your character from being revived."
+
+	if(!isobserver(src)) // Somehow
+		return
+	if(!can_reenter_corpse)
+		to_chat(src, "<span class='warning'>You are already set to DNR!</span>")
+		return
+	if(!mind || QDELETED(mind.current))
+		to_chat(src, "<span class='warning'>You have no body.</span>")
+		return
+	if(mind.current.stat != DEAD)
+		to_chat(src, "<span class='warning'>Your body is still alive!</span>")
+		return
+
+	var/choice = alert(src, "If you enable this, your body will be unrevivable for the remainder of the round.", "Are you sure?", "Yes", "No")
+	if(choice == "Yes")
+		to_chat(src, "<span class='boldnotice'>Do Not Revive state enabled.</span>")
+		can_reenter_corpse = FALSE
+		if(!QDELETED(mind.current)) // Could change while they're choosing
+			mind.current.med_hud_set_status()
+
 /mob/dead/observer/proc/dead_tele()
 	set category = "Ghost"
 	set name = "Teleport"

code/modules/mob/living/carbon/carbon.dm

@@ -215,7 +215,7 @@
 	if(stat == DEAD)
 		if(M != src)
 			M.visible_message("<span class='notice'>[M] desperately shakes [src] trying to wake [p_them()] up, but sadly there is no reaction!</span>", \
-			"<span class='notice'>You shake [src] trying to wake [p_them()] sadly they appear to be too far gone!</span>")
+			"<span class='notice'>You shake [src] trying to wake [p_them()], sadly they appear to be too far gone!</span>")
 		return
 	if(health >= HEALTH_THRESHOLD_CRIT)
 		if(src == M && ishuman(src))

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>")