bug#26871: [External] : bug#26871: 25.2; Support revert-buffer for Customize buffers

[Drew Adams <drew.adams@oracle.com>]

> > The only way I'm aware of to refresh a Customize buffer when things
> > have changed externally is to kill the buffer and recreate it.
> >
> > It would be convenient if `revert-buffer' was supported, and bound
> > to "g" as usual.
> 
> Yeah, reverting in Customize buffers can be convenient, especially when
> developing (and loading new stuff), so I've added this to Emacs 28.
> (But it uses the global `C-x x g' binding, because the Customize buffer
> is semi-editable, so it'd be confusing (and error-prone) to bind `g' to
> this outside of the editable fields.)

1. `revert-buffer' is very useful for Customize.
Thanks for adding it.


2. FWIW, I disagree that `g' should not be bound to
`revert-buffer' in Customize buffers (outside of
editable fields, obviously).

Your logic would have us also remove the bindings
of `n', `p', `q', `u', `DEL'...
`g' should be bound to `revert-buffer'.


3. A related feature is to be able to update, for
Customize, all options, faces, or both, to their
current states as set outside Customize.  IOW,
not just revert the current Customize buffer but
update Customize more generally.

My library `cus-edit+.el' offers that: commands
to tell Customize to sync its understanding with
the wider Emacs world for (1) all options, (2)
all faces, or (3) all options and faces.  Command
`customize-update-all' does #3.

You can put `customize-update-all' on an idle
timer to keep Customize synced with what happens
outside of Customize, so you can change anything
anywhere in Emacs and have Customize reflect that.

When you exit Emacs, you can be told about all
changes and asked if you want to save them.

https://www.emacswiki.org/emacs/CustomizingAndSaving#summary