Version switcher provides explicit URLs

[choldgraf]

This removes the url_template parameter of our version switcher, and instead has users explicitly give a URL for each of the versions specified in their version switcher JSON.

closes #600

[damianavila]

LGTM, I like the explicitness of the approach.

[damianavila]

After fixing the merge conflicts, I realized one docs json snippet should be updated.

[damianavila]

@choldgraf, pushed a new commit after fixing the merge conflicts, feel free to re-review and merge this one.

[choldgraf]

Thanks @damianavila ! Just to confirm, I believe that @tupui was 👍 on this change - if anybody else objects please weigh in. Otherwise I'll merge this in a day or two.

[tupui]

Yes I am 👍 Thanks for doing this! Can't wait to use it.

[larsoner]

In the future when options are removed, it might be worth emitting a warning in the sphinx build. If I had seen a message like:

WARNING: The configuration variable html_theme_options['switcher']['url_template'] is no longer supported, set URLs in JSON directly

it would have saved me a bit of pain.

Also the failures are silent currently as our links are now to https://mne.tools/undefinedindex.html for example rather than what they were before (e.g., https://mne.tools/0.22)

[choldgraf]

oops - sorry that this created some pain for you. Maybe I was mistaken but I thought we had not yet released this feature which is why I didn't think to deprecate it...I might have missed a release though :-/

[larsoner]

It looks like pandas hit it and their workaround was to pin to 8.0.0, so it was probably in there? Not sure though...

[choldgraf]

yep you are correct, my bad :-(

https://github.com/pydata/pydata-sphinx-theme/releases/tag/v0.8.0