bug#33007: 27.0.50; Proposal for function to edit and return string

[Eli Zaretskii]

> From: Michael Heerdegen <michael_heerdegen@web.de>
> Cc: Eli Zaretskii <eliz@gnu.org>,  33007@debbugs.gnu.org
> Date: Thu, 11 Oct 2018 15:31:15 +0200
> 
> Some minor thoughts: The input buffer should be more controllable: modes
> and keymap shouldn't be fixed.  Also, it should be possible to prefill
> the buffer with a string describing what the user is expected to do, and
> which is ignored after the user has finished.

Don't we already have something like that in Customize and/or in EWW,
where they allow the user to fill fields in a form?