fix: decomposing leaves now check for falling.

leaves now call `minetest.check_for_falling` at their position when
decomposing into air. this fixes an error where falling nodes would be
left floating above decomposing leaves once said leaves disappeared.

mods/bg_tree/decompose.lua

@@ -99,6 +99,7 @@ blockgame.register_increasing_abm({
 			minetest.set_node(pos, {name = "bg_terrain:dirt"})
 		else
 			minetest.remove_node(pos)
+			minetest.check_for_falling(pos)
 		end
 	end,
 })