Stops vampires from draining blood if their mouth is blocked (#9157)

What it says in the title. Should stop vampires from sucking people while wearing space suits.

code/game/gamemodes/vampire/vampire_powers.dm

@@ -41,6 +41,10 @@
 	if(T.head && (T.head.item_flags & AIRTIGHT))
 		to_chat(src, span("warning", "[T]'s headgear is blocking the way to the neck."))
 		return
+	var/obj/item/blocked = check_mouth_coverage()
+	if(blocked)
+		to_chat(src, SPAN_WARNING("\The [blocked] is in the way of your fangs!"))
+		return
 	if (vampire.status & VAMP_DRAINING)
 		to_chat(src, span("warning", "Your fangs are already sunk into a victim's neck!"))
 		return

html/changelogs/alberyk-vampirenerf.yml

@@ -0,0 +1,6 @@
+author: Alberyk
+
+delete-after: True
+
+changes: 
+  - tweak: "Vampires can no longer suck blood if their own mouth is being blocked by something."