Improve design of the "RTD box"

[AlbertMitjans]

I believe the way the ReadTheDocs version box is shown could be improved:

[humitos]

Hi 👋🏼 , I'm one of the developers from Read the Docs that's currently working on the "RTD box" ¹. The image shown in the description is using "the old implementation" of the flyout. Currently, we have published our "beta addons" containing the flyout as well. We tried to keep the look&feel pretty similar to avoid surprises on users when migrating to the new flyout. However, we will be working on a completely re-design from scratch -- but we don't have an ETA for this re-design yet.

On the other hand, we will be providing an API to access all the JSON data needed to generate and integrate the flyout by the theme authors respecting the look&feel of the theme and also change its position if wanted. I worked on a POC to show this on the Read the Docs Sphinx theme at readthedocs/sphinx_rtd_theme#1526. As you can see there, the flyout is integrated into the navbar at the bottom left, instead of being floating at bottom right.

The pattern where the event readthedocs-addons-data-ready is triggered and theme developers can subscribe, is not yet deployed since we a looking for feedback from theme authors and developers about it to know if this pattern will be helpful for them to integrate in a better way with Read the Docs. I'd appreciate any feedback you may have 🙏🏼

Footnotes

1. BTW, we call it flyout 😄 ↩