Consider making hoverxref_auto_ref = True the default?

[astrojuanlu]

When @ericholscher and @humitos discussed this privately in April 2020, this was @humitos opinion:

it does not enable :ref: by default because I think it's too aggresive

However, after writing readthedocs/blog#144 I agree with @ericholscher that the default is a bit too conservative. I see the intention (providing a :hoverxref: role) but I think it has less friction if no conf.py changes are needed to see the extension in action with an existing project. On the other hand, "something migh break", but I think changing the default will actually help us detect such breakage.

Thoughts?

[ericholscher]

I'm 👍 on defaulting to the most possible referencing, since that is what I'd expect as a user when I enable the extension. It feels weird to default to a subset of possible links, and really confusing to readers of the docs when random internal links don't hover.

[KanchiMoe]

I would decline, because :ref: (when combined with autosectionlabel) allows you to link to any header in the documentation - which, isn't something you can do without this extention.

Having hoverxref_auto_ref be true by default would mean that any interlinking using ref will show a tooltip.

I think the current set up is ideal where using :hoverxref: allows you to control having when a tooltip shows up.

[ericholscher]

I'd really like to see this here.

Also I set this up, and got this error.. 🤔

Using default style (tooltip) for unknown typ (ref). Define it in hoverxref_role_types.

[ericholscher]

cc @humitos -- I think there's some "first run" improvements we could do here.