DOC: update ufunc tutorials to use setuptools

[JuliaPoo]

See #22027. Currently ufunc tutorials use depreciated distutils which is removed in Python 3.12. In addition, I've updated the sample output and fixed a mistake in the last example.

[mattip]

I wonder if we could convert this tutorial (and the others like the cython one to use meson. The extending random examples have a meson.build file, but the documentation is a little sparse. The f2py migration guide is a little better, but could also use some fleshing out.

[rgommers]

Thanks @JuliaPoo!

I wonder if we could convert this tutorial (and the others like the cython one to use meson.

I think that is a much larger exercise, and best done separately if someone has energy for that. setuptools is still a valid and common way of building extensions against numpy, so no need to get rid of that. Migrating from numpy.distutils to setuptools is a nice improvement in itself, that makes things work on Python 3.12. In an ideal world, we'd have examples for all the popular build backends (at least meson-python, scikit-build-core and setuptools) everywhere - but that's quite a bit of work.

[mhvk]

Thanks, great to have documentation that actually works! And thanks for going through it carefully and ensuring the outputs are actually correct, etc.

Also indeed fine to just use setuptools for these examples - others can be added later if need be.

All my comments are nitpicks, of the "please align" and "please combine lines" type.

[JuliaPoo]

Okie I've modified the PR to these comments

[mhvk]

Nice, thanks! Looks all OK now, so let's get this in.

[charris]

@rgommers already backported.

[rgommers]

oops sorry, I missed that. thanks!