Doors: Pass pointed_thing to on_rightclick() callback

This is an omission technicality. The callee should be able
to trust this isn't `nil`

mods/doors/init.lua

@@ -254,7 +254,7 @@ function doors.register(name, def)
 			local pdef = minetest.registered_nodes[node.name]
 			if pdef and pdef.on_rightclick then
 				return pdef.on_rightclick(pointed_thing.under,
-						node, placer, itemstack)
+						node, placer, itemstack, pointed_thing)
 			end
 
 			if pdef and pdef.buildable_to then