custom-enchant 
Adds a custom enchantment to a player's selected item.
Syntax 
- custom-enchant <entities: target> <custom_enchantment: string> [level: integer]
Arguments 
- <entities: target>
 Specifies the target(s).
- <custom_enchantment: string>
 Any custom enchantment registered with- customEnchantmentRegistry.
- <level: integer>
 Specifies the enchantment level.
