Enable directly invoking the default path completions

[Jakobuo]

Basics

• [x] I have done a basic search through the issue tracker to find similar or related issues.
• [x] I have made myself familiar with the available features of Nushell for the particular area this enhancement request touches.

Related problem

I have a custom command that cares about files with specific extensions. Whilst it is simple enough to make a basic completions command that returns all files in the current directory with the right extensions, it would be quite nice if I could simply invoke the default path completions and then filter out the things I don't care about. This would safe me from having to either leave the completions at a very basic level, or having to reimplement the nontrivial completion logic in my completer.

Describe the solution you'd like

Make it possible to get path completions by executing a command, or in some other way make them available for custom completers.

Describe alternatives you've considered

No response

Additional context and details

No response