Agreed with Primus. There's totally not a way to get the enchantment name from an id. Edit: I did some investigations and it turns out(or I couldn't find it) that there isn't a way to get the name of the enchantment by id. (correct me if I'm wrong) So alternatively, you can just look at pocketmine's source https://github.com/pmmp/PocketMine-MP/blob/stable/src/pocketmine/item/enchantment/Enchantment.php and find it out yourself.
Why bump an already-solved thread? And what you've said about IDE having auto complete won't solve his problem.