Porting updates related to material datums. (#12317)

* Porting updates related to material datums.

* art_type

* oh oh

code/game/objects/items/tanks/tanks.dm

@@ -60,14 +60,19 @@
 	H.update_action_buttons_icon()
 
 
-/obj/item/tank/New()
-	..()
+/obj/item/tank/Initialize()
+	. = ..()
 
 	air_contents = new(volume) //liters
 	air_contents.temperature = T20C
 
+	populate_gas()
+
 	START_PROCESSING(SSobj, src)
 
+/obj/item/tank/proc/populate_gas()
+	return
+
 /obj/item/tank/Destroy()
 	if(air_contents)
 		qdel(air_contents)
@@ -78,9 +83,9 @@
 /obj/item/tank/examine(mob/user)
 	var/obj/icon = src
 	. = ..()
-	if (istype(src.loc, /obj/item/assembly))
+	if(istype(src.loc, /obj/item/assembly))
 		icon = src.loc
-	if(!in_range(src, user))
+	if(!in_range(src, user) && !isobserver(user))
 		if (icon == src)
 			. += "<span class='notice'>If you want any more information you'll need to get closer.</span>"
 		return