Add SciPy 1.16.0

[tylerjereddy]

• Add SciPy 1.16.0. I just did make dist and make upload steps.
• Note that the PR for adding 1.15.3 is still open, so an argument could be made to try to include that here as well, though I haven't done that (if we merge this first, some changes will be needed over there, since 1.16.0 becomes the latest stable release).
• As a reminder, version switcher shenanigans are likely until things are merged both here and in the main repo.

[tylerjereddy]

ok, I rebased this/resolved merge conflicts after Evgeni's recent merge of the other PR

[ev-br]

Thanks Tyler, and thanks for managing the release!