RE: `declare-function' docu

[Drew Adams]

> > Similarly, help-fns+.el.
> 
> I see you’re the author.  Do you plan to
> contribute it to Emacs core or GNU ELPA?

I've offered its code, and that of all my
libraries, several times.  A few things from
help-fns+.el have been integrated (e.g.
`describe-keymap' - see Emacs bug #30660),
albeit in a somewhat lesser form.  But in
general there's been little to no interest.

>From my point of view, I'd much prefer that
vanilla Emacs offer such features, so I'd no
longer need to maintain separate libraries.

In the particular case of adding links from
*Help* to manuals, I think the approaches
being looked at now probably make sense -
they may be performant.

But some aspects of the simple approach to
this taken in help-fns+.el might also help -
such as user choice of whether to find lookup
addresses ahead of time or just when following
links.  If the cost of systematically finding
them ahead of time isn't too great, fine.

Besides lookup cost, letting users specify
which manuals to check can be useful - the set
of manuals available differs for different
users/platforms, and which ones to link to
(search) is a question for users.