When knockback is applied to a player as a result of the AoE (area of effect) of a smash attack with the mace weapon, no knockback event is fired. I assume the appropriate one would be `EntityKnockbackByEntityEvent`.

Not having this event fire means that protection plugins cannot ensure players not being pushed out of protective zones by others in cases where damaging other mobs is possible. It also makes denying pvp/knockback inconsistent.

To reproduce
Have a plugin listening to `EntityKnockbackEvent`.

public class KnockbackListener implements Listener {
    @EventHandler
    public void onKnockback(EntityKnockbackEvent e) {
        Bukkit.getLogger().info("Knockback on " + e.getEntityType());
    }
}

Hit a mob next to the player with a mace while falling from at least 1.5 blocks.

The listener only gets triggered for the mob that was directly hit.