taking care over sphinx version

[ddkohler]

Tests were recently failing for sphinx docs build. The root cause is sphinx 8.0.0 replaced some function references that sphinx-gallery uses. We have pinned our version of "sphinx-gallery<0.8.2" back about 4 years, but it appears the new one has not adapted to the changes yet either.

For now, we will pin to sphinx<8.0, but we will probably have to revisit this issue in the future, especially since we are pinned to a very old sphinx-gallery version.

[kameyer226]

I'd like to ask sphinx about these references, do you have a list of functions that were deprecated?

[ddkohler]

They are documented in the changelog
https://www.sphinx-doc.org/en/master/changes/8.0.html#release-8-0-1-released-jul-30-2024

Just to be clear, this is an upstream incompatibility--we have to wait for sphinx-gallery to adopt the sphinx 8.x changes.