Misc fixes

Applies cooldown to the 'use item on self' button, and makes the 'you don't have an item' text a little more informative.

Also re-renames 'Custom Subtle' back to 'Subtle (Custom)', I didn't test this originally because I thought my pants were really big, and turns out that doing this just makes it first in the list for subtles, which is WORSE! I'm not sure what to rename it, so! Let's just put it back.

Also touches up simple mobs and mouse holes so that simple mobs (such as mice) can click on mouse holes to interact with them! Turns out mice couldn't properly use mouse holes, and that seems like a shame! This is fixed now. Incidentally, borgs can also use mouse holes now.

code/_onclick/hud/human.dm

@@ -160,10 +160,8 @@
 		using.alpha = HUD.ui_alpha
 		adding += using
 
-		using = new /obj/screen()
+		using = new /obj/screen/useself()
 		using.icon = HUD.ui_style
-		using.icon_state = "use"
-		using.name = "use held item on self"
 		using.screen_loc = ui_swaphand2
 		using.color = HUD.ui_color
 		using.alpha = HUD.ui_alpha
@@ -424,3 +422,15 @@
 /obj/screen/wizard/energy
 	name = "energy"
 	icon_state = "wiz_energy"
+
+/obj/screen/useself
+	name = "use held item on self"
+	icon_state = "use"
+	var/next = 0
+
+/obj/screen/useself/proc/can_use(var/mob/living/carbon/human/h, var/obj/item/i)	//Basically trying to use the item this way skips the cooldown
+	if(world.time >= next)														//And trying to check the cooldown doesn't work because when you click the UI it sets a cooldown
+		next = h.get_attack_speed(i)											//So instead we'll just put a cooldown on the use button and apply the item's cooldown to the player
+		h.setClickCooldown(next)												//Otherwise you can click the button and yourself faster than the normal cooldown. SO WE SET BOTH!!!!
+		next += world.time
+		i.attack(h, h)

code/_onclick/hud/screen_objects.dm

@@ -477,13 +477,14 @@
 			usr.down()
 
 		if("use held item on self")
+			var/obj/screen/useself/s = src
 			if(ishuman(usr))
 				var/mob/living/carbon/human/u = usr
 				var/obj/item/i = u.get_active_hand()
 				if(i)
-					i.attack(usr, usr)
+					s.can_use(u,i)
 				else
-					to_chat(usr, "<span class='notice'>You're not holding anything to use.</span>")
+					to_chat(usr, "<span class='notice'>You're not holding anything to use. You need to have something in your active hand to use it.</span>")
 
 		if("module")
 			if(isrobot(usr))