bug#33443: 26; Doc of Edit Abbrevs mode

[Eli Zaretskii]

> Date: Tue, 20 Nov 2018 08:54:08 -0800 (PST)
> From: Drew Adams <drew.adams@oracle.com>
> 
>  Edit-Abbrevs mode defined in `abbrev.el' (`edit-abbrevs-mode'):
>  Major mode for editing the list of abbrev definitions.
> 
>  This mode runs the hook `edit-abbrevs-mode-hook', as the final or 
> penultimate step
>  during initialization.
> 
>  key             binding
>  ---             -------
> 
>  C-c             Prefix Command
>  C-x             Prefix Command
> 
>  C-c C-c         edit-abbrevs-redefine
> 
>  C-x C-s         abbrev-edit-save-buffer
>  C-x C-w         abbrev-edit-save-to-file
> 
> [One of those help lines is 82 chars long, BTW.]

Yes.

> You have to roam around in the source file a bit to find out what you're
> looking at and what you can do with it.  In particular, the doc of
> `edit-abbrevs' tells you what you're looking at and what you can do with
> what you're looking at. It is...

I added to the doc string of 'edit-abbrevs-mode' a reference to
'edit-abbrevs', where this stuff is described.  This mode is
specifically designed for editing in such a buffer, so I see no need
to repeat the documentation there, as users are unlikely to turn that
mode by themselves.

> ("Current buffer" is wrong here, BTW, as what is meant
> by it is not the buffer of buffer *Abbrevs* but the
> buffer that you came from to create buffer *Abbrevs*.)

No, "current buffer" is not wrong, since the editing buffer is
prepared for editing abbrevs of the buffer that is current when the
function is invoked.

> Similarly, the doc in the Emacs manual (node `Abbrev Concepts' is not
> very helpful.  It tells you how you can use (expand) an existing abbrev,
> but it says nothing about how to create an abbrev, for instance.

"Abbrev Concepts" is not where this is described.  Please read the
following sections.

Thanks.