Would be great if a timer could be added to the chat message when trying to spawn a horse (You have called your horse recently, cooldown left: 00:00:00) so players know when they can spawn a new one.

There is a timer in seconds, but you probably had not deleted your lang file upon updating to v1.0.0, so it's not displayed. Try adding {0} to the Cooldown lang message, or delete the lang file completely, it will be refreshed with correct strings.

That was it, thank you! :D