Updated mobs' README.txt and added comment warning

- Added comment to warn a change of our
- Updated README.txt in mobs mod. However, Ombridride will have to do a lot of works, the mod have been changed again (no more steps, parameters
  deleted, etc).

mods/mobs/api.lua

@@ -958,6 +958,7 @@ function mobs:register_spawn(name, nodes, max_light, min_light, chance, active_o
 			-- spawn mob half block higher
 			pos.y = pos.y - 0.5
 			minetest.add_entity(pos, name)
+
 		end
 	})
 end
@@ -1016,6 +1017,7 @@ function do_tnt_physics(tnt_np,tntr)
             end
     end
 end
+--MODIFICATION MADE BY MFF
 
 function mobs:register_arrow(name, def)
 	minetest.register_entity(name, {