bug#31636: 27.0.50; lockfile syntax searchable from info manual

[Eli Zaretskii <eliz@gnu.org>]

> From: Robert Pluim <rpluim@gmail.com>
> Cc: mail@bradyt.com,  31636@debbugs.gnu.org,  eggert@cs.ucla.edu,  npostavs@gmail.com
> Date: Fri, 01 Jun 2018 12:47:54 +0200
> 
> > This should use @var{user}, @var{host} etc. for the components of the
> > target file name, and it should explain shortly what each component
> > stands for.
> 
> I donʼt see any difference in the visual appearance from using @var,

In Info format, you won't see any difference, because @var up-cases
its argument in that format.  But in the printed manual the visual
appearance of @var is very different: it gives the argument the
slanted typeface and doesn't up-case it.

> (I noticed that texinfo.el has no bindings for inserting @ref,
> @xref, and @pxref, should I add some?  C-cC-c[rp] are free, but x is
> already used for @example, so 'C-cC-cX'? Or maybe 'C-cC-cC-x' for
> @xref?)

How about using just "C-c C-c r" and letting it intuit the exact form
from the context?  @xref is only used at the beginning of a sentence,
and @pxref should normally follow an open paren.

In any case, adding this to texinfo.el would be a welcome addition, I
think.

The patch LGTM, thanks.