[patch v1] manual: make @manpageurl more specific to each output

[Florian Weimer]

* DJ Delorie:

> Florian Weimer <fweimer@redhat.com> writes:
>>> +``\func\(\sec\)'' (@url{https://man7.org/linux/man-pages/man\sec\/\func\.\sec\.html,,Latest: \func\(\sec\)})
>>
>> Would it make sense to move the Latest: out of the linked part?
>
> It works either way; the user could click on the word "latest" to jump
> to the latest version.  I prefer giving the user a larger target to
> hit.

The current Info version reads like this:

  This documentation is a stub.  For additional information on this
  function, consult the manual page "poll(2)" (Latest:
  <https://man7.org/linux/man-pages/man2/poll.2.html>).  *Note Linux
  Kernel::.

The quotes seem redundant, the poll(2) looks like sufficient markup to
me.  Maybe use this instead?

  This documentation is a stub.  For additional information on this
  function, consult the manual page poll(2) (online:
  <https://man7.org/linux/man-pages/man2/poll.2.html>).  *Note Linux
  Kernel::.

The HTML version looks like this:

  This documentation is a stub. For additional information on this
  function, consult the manual page “poll(2)” (Latest: poll(2)). See
  Linux (The Linux Kernel).

Where the “Latest: poll(2)” is the hyperlink.  This too looks redundant.
I think readers of a web page expect an unversioned link.  We can
explain that the online links always go to the latest in the Linux
section.  So maybe this?

  This documentation is a stub. For additional information on this
  function, consult the manual page poll(2). See Linux (The Linux
  Kernel).

Or maybe clarify that this is an external source, like this?

  This documentation is a stub. For additional information on this
  function, consult the manual page poll(2) (external
  specification). See Linux (The Linux Kernel).

(The last part is just what the @xref macro does, even though it is a
bit awkward.)


The PDF version looks like this:

  int poll (struct pollfd *fds, nfds t nfds, int timeout)          [Function]
    This documentation is a stub. For additional information on this function,
    consult the manual page “poll(2)” (Latest: poll(2)).  See Section 1.2.6
    [Linux (The Linux Kernel)], page 12.

I think we should include the URL there.  I think the same construct as
the info version should be used.

This means that the HTML version is the outlier, and you could use
@ifhtml and @ifnothtml to produce the different linking style there.

Thanks,
Florian