Add option to fail docs build on gallery example execution error

[melissawm]

References and relevant issues

Closes napari/napari#6392
Depends on #255

Description

Added a sphinx gallery option to fail the docs build on example execution failure.

Right now, this should fail on CI due to one of our example failing, but the docs build will anyway depend on the #255.

[psobolewskiPhD]

Build is failing due to sphinx_tags release today, which has:
melissawm/sphinx-tags@6351df0

This import requires sphinx 5.1...
I think we can lift the pin here to <6 and in https://github.com/napari/napari-sphinx-theme

Edit: I'm going to test it...

[psobolewskiPhD]

I bumped the pin in napari-sphinx-theme and in this repo to <6, and the docs built locally with the new sphinx_tags.
I'll open PRs.
So this one either needs to pin pack sphinx_tags or we go with the <6

[melissawm]

Thanks for checking that @psobolewskiPhD - so I guess this leaves us a choice, really. Do we cut a new napari-sphinx-theme release, or do we go with the new theme infrastructure, that already supports any sphinx<6? (We can also just pin sphinx-tags for now)

[psobolewskiPhD]

Yes! This seems as good a reason as any to cut over to your theme!

[melissawm]

ok - it looks like this is "failing correctly" 😅

[psobolewskiPhD]

So the fail--expected--is vortex right? And that is fixed by napari/napari#6475

[psobolewskiPhD]

Going to merge main, because vortex fix has been merged. Then if everything is green this should be good to go!

[psobolewskiPhD]

Looks good!
❤️