Changes all cases of update_icons(), updateicon(), UpdateIcon() etc. to update_icon(). (#9432)

update_icons(), UpdateIcon() and updateicon() are now changed to be update_icon().

Many interactions expect a target to have an update_icon(), so they should all be the same.

Also fixed some stuff that was using relative pathing, along the way.

code/modules/admin/topic.dm

@@ -647,7 +647,7 @@
 		//strip their stuff and stick it in the crate
 		for(var/obj/item/I in M)
 			M.drop_from_inventory(I, locker)
-		M.update_icons()
+		M.update_icon()
 
 		//so they black out before warping
 		M.Paralyse(5)