feat: allow results in async_oneshot_finder

[fdschmidt93]

The use case for this in telescope-file-browser is prepending the current directory in the folder browser when using fd, since fd of course blocks a lot less than scan dir in large repos.

The canonical shell equivalent of that would be echo "." && fd -t d` (see also sharkdp/fd#364) but I don't think plenary Jobs supports that.

I guess it's a bit of an edge case and I honestly couldn't think of other good uses. At the same time it should be pretty harmless because finders yells if results are passed, so you'd have to user the lower level api anyways.

[Conni2461]

We no longer do plenary jobs in finders (we have some piping support with after_success in plenary jobs tho). We now use _.luas LinePipe implementation

I think we can do this, so i merge this. But you can also think about a custom finder that works with scan_dir_async. It can stream in data so this should work almost as good as fd and oneshot. (I know about your timing situation right now, so this is just a suggestion).