Adds cooldown to Xenomorph neurotoxin, changes stun to knockdown (#18919)

* Adds cooldown to Xenomorph neurotoxin, changes stun to knockdown

* Neurotoxin now works when implanted in humans

* Tidying

* More tidying

* More tidying

code/modules/mob/living/carbon/alien/humanoid/alien_powers.dm

@@ -89,10 +89,13 @@ Doesn't work on other aliens/AI.*/
 	set name = "Spit Neurotoxin (50)"
 	set desc = "Spits neurotoxin at someone, paralyzing them for a short time."
 	set category = "Alien"
+	var/obj/item/organ/internal/xenos/neurotoxin/organ = locate() in internal_organs
 
-	if(powerc(50))
+	if(powerc(50) && !organ.neurotoxin_cooldown)
 		adjustPlasma(-50)
-		src.visible_message("<span class='danger'>[src] spits neurotoxin!", "<span class='alertalien'>You spit neurotoxin.</span>")
+		visible_message("<span class='danger'>[src] spits neurotoxin!</span>", "<span class='alertalien'>You spit neurotoxin.</span>")
+		organ.neurotoxin_cooldown = TRUE
+		addtimer(VARSET_CALLBACK(organ, neurotoxin_cooldown, FALSE), organ.neurotoxin_cooldown_time)
 
 		var/turf/T = loc
 		var/turf/U = get_step(src, dir) // Get the tile infront of the move, based on their direction

code/modules/projectiles/projectile/bullets.dm

@@ -282,12 +282,13 @@
 	icon_state = "neurotoxin"
 	damage = 5
 	damage_type = TOX
-	weaken = 10 SECONDS
+	stamina = 40
+	knockdown = 10 SECONDS
 
 /obj/item/projectile/bullet/neurotoxin/on_hit(atom/target, blocked = 0)
 	if(isalien(target))
-		weaken = 0
-		nodamage = 1
+		knockdown = 0
+		nodamage = TRUE
 	. = ..() // Execute the rest of the code.
 
 /obj/item/projectile/bullet/cap

code/modules/surgery/organs/subtypes/xenos.dm

@@ -141,6 +141,8 @@
 	slot = "neurotox"
 	origin_tech = "biotech=5;combat=5"
 	alien_powers = list(/mob/living/carbon/alien/humanoid/proc/neurotoxin)
+	var/neurotoxin_cooldown = FALSE
+	var/neurotoxin_cooldown_time = 5 SECONDS
 
 /obj/item/organ/internal/xenos/resinspinner
 	name = "xeno resin organ"//...there tiger....