[SIMBAD] Add emtpy response warning

[ManonMarchand]

Hi astroquery devs,

This PR adds a NoResultWarning when a SIMBAD query returns an empty table. This should fix #3060 .

[bsipocz]

This looks good thank you.

I see the doctest failing locally, but it's some weird issue that I don't yet tracked down as it not always showing up in CI. So I'll just leave it as is now.

Thanks!

[ManonMarchand]

Oh? Could you show your local failure? I don't have any.

[bsipocz]

It's just messing around ELLIPSIS and whitespace, it really is a local issue most of the time.

But for this one, I see it in CI, too: https://github.com/astropy/astroquery/actions/runs/9814474694/job/27525866043#step:5:13186

(just restarted this run after merging a bunch of PRs this morning, so any failures your see there are on main)

[ManonMarchand]

Maybe I have something different in my config, because I see the failure the other way, and I patched the width of the output in 9f65c6f
I'll have a look on my side too

[bsipocz]

I would say don't worry about it for now (or we should just patch things up for the weekly CI to have fewer issues, but then again it doesn't really matter. I'll open an issue upstream for doctestplus as ideally, we should handle it within it.

(Also, maybe you have an older pytest-doctestplus version? If yes, that may help to narrow down when and why this became a problem).