Autojump argument parsing

[Direwolfesp]

I've changed the number of arguments of def --env j [dir] to def --env j [...dir], this change makes the behaviour more like the j autojump you can find in other shells where an arbitrary number of inputs are given to it.

ie.
In zsh:

In nushell old j:

In nushell new j:

[fdncred]

Thanks