mv: expose main functionality for nushell

[PThorpe92]

References #5293
@tertsdiepraam I did try to base if off the PR you mentioned in the issue.

The reason for the change of variable names (b -> opts) in non-public functions, is simply to match the new naming. If this is something that isn't desired, let me know.

Let me know of any additional changes you are looking for.

Also, everything did end up working out in our CI (eza), as well as further testing for uutils-term-grid. Was removing the Alignment field all that you were waiting on to publish? Although now that we know it will be a drop-in replacement, there certainly isn't a rush. Thanks, we definitely appreciate it.

EDIT: Had to fix clippy warning for failed CI anyway so those ;'s are just other random warnings I saw.

[github-actions]

GNU testsuite comparison:

Congrats! The gnu test tests/tail/truncate is no longer failing!

[tertsdiepraam]

Great! Thanks! I have some small suggestions. You could also take a quick look at the cargo doc output, to see how it looks there and maybe fix up the formatting.

[tertsdiepraam]

I like it! Just one last request: could you put the clippy fixes in a separate commit?

[tertsdiepraam]

Btw, I'm getting ready to publish term grid: uutils/uutils-term-grid#20. Hopefully it will be up today.

[cakebaker]

I think you have to rebase because your branch contains code I removed a few days ago in #5347 and so the tests fail.

[github-actions]

GNU testsuite comparison:

GNU test failed: tests/mv/mv-n. tests/mv/mv-n is passing on 'main'. Maybe you have to rebase?

[PThorpe92]

Ahh. yeah I didn't see that so i must have messed up the merge conflict. Rebased so it should pass now 👍

@tertsdiepraam big thanks :D

[cakebaker]

Thanks for your PR :)

[tertsdiepraam]

Thanks @PThorpe92!