Documentation Link

https://matplotlib.org/devdocs/

Problem

In #27658 I updated the version switcher JSON link so it came from the circleCI builds when building on circleCI. It seems like https://matplotlib.org/devdocs/ is now trying to load a version switcher from circleCI too, so we need to:

1. Work out how to detect if deploying to devdocs
2. Set the version switcher URL in docs/conf.py correctly if this is the case

Suggested improvement

No response