bug#31405: 25.3; Python.el doesn't provide infos to info-lookup-symbol

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Thu, 12 Aug 2021 17:21:58 +0200
> Cc: 31405@debbugs.gnu.org, Stefan Kangas <stefan@marxist.se>,
>  Noam Postavsky <npostavs@gmail.com>, seb@k-7.ch
> 
> "Basil L. Contovounesios" <contovob@tcd.ie> writes:
> 
> > In my case I have to override it as
> >
> >   (with-eval-after-load 'info-look
> >     (info-lookup-add-help
> >      :mode 'python-mode
> >      :doc-spec '(("(python3.9)Index"))))
> >
> > to match the name and version of the manual installed by Debian.
> 
> I've now adjusted the code to look for the 3.9 manual

If Debian is including the version in the file name, and we want to
support that, I think we should have a defcustom for users to control
which version they want Emacs to look for.  Or maybe we should allow a
list of file names there, and then we could mention all the known
names for reasonably recent versions of Python.

Again, the Info system is not designed to support that.  For example,
hyperlinks from other manuals won't work reliably, and you'd have
trouble with the system-wide DIR file, if you ever dare updating it
outside of Debian's control.