Description

Add a way to create/mark certain groups as non-assignable.

There are times where groups exist solely to provide a base inheritance for other groups. ex.

donor:
	vip
	vip+
	
staff:
  mod
  admin

It would be nice if you were able to mark these groups as non-assignable, so that the commands:

• user parent add
• user parent set
• etc..

fail when this group is passed in.

Proposed Behaviour

Maybe have a special luckperms node (similar to the way group displaynames work):
assignable.false (or maybe just assignable with the value false)

And applicable commands would then check the value of this node when tab completing and when the group is passed as an argument.

Extra Details

No response

This is already possible with argument based command permissions, by allowing to set/add all groups but setting to false the permissions to set or add the specific groups you don't want to be assignable.
These work on top of the base command permissions with all the mentioned extra checks.

^^ The specific part of that page you need is https://luckperms.net/wiki/Argument-based-command-permissions#checks-when-a-player-makes-changes-with-a-set-of-specific-arguments :)

Thank you, always a pleasure! 🤜🏽🤛🏽