bug#73286: [PATCH] Add foldout command for widening to current fold

[Eli Zaretskii <eliz@gnu.org>]

> From: Paul Nelson <ultrono@gmail.com>
> Date: Mon, 16 Sep 2024 01:38:35 +0200
> 
> The foldout package, which "zooms in" on document sections by
> narrowing the buffer, doesn't play well with Emacs's other narrowing
> features: after narrowing further within a fold, there's no easy way
> to widen back to the fold's boundaries.
> 
> This patch introduces foldout-widen-to-current-fold, a command that
> widens to the current fold level (or to the whole buffer if not in a
> fold).
> 
> Example usage:
> - Use foldout-zoom-subtree to zoom in on some section.
> - Use narrow-to-defun to edit some function.
> - Use foldout-widen-to-current-fold to return to the scope of the
> zoomed-in section.
> 
> Any feedback welcome.

Thanks.  This new feature LGTM, but I'm not convinced we should have a
separate key binding for this new command by default.  If we want to
have a default key binding at all, maybe we should make "C-c C-x"
invoke this command when given a negative argument.

Stefan and Andrea, WDYT?