hoverxref new name

[humitos]

I think it could be a good opportunity to re-brand this feature and find a good name for it --not only because the hoverxref name is terrible, but also because it's not tied to "xref" anymore, since that's a Sphinx concept

(from Slack)

We should find some good ideas for this name and more forward with one. I'm using tooltips.js for now.

[agjohnson]

Definitely agree we should update this. Going back to the same conversation around the name of this repo, there is probably some product brainstorming here even.

"Tooltip" to me sounds a bit too low level. The implementation is using a tooltip underneath, but we probably want to communicate that this does something on top of "tooltips".

Also, to my point with the other issue and "client", if we asked a user what "tooltip.js" does, they probably wouldn't guess that it embeds popup documentation.

So for that, I'd get more specific with this feature and the "readthedocs-client" rename. For this feature, perhaps more along the lines of "popup docs", "embedded docs", "hover docs"?

[humitos]

Material for MkDocs calls it "⚡ Instant previews": squidfunk/mkdocs-material#6704