martin rudalics <rudalics@gmx.at> writes:

> This commit
>
> commit 866e3c050fe64fee81f29a335a50a11b2562422e
> Author: Lars Ingebrigtsen <larsi@gnus.org>
> Date:   Thu Apr 28 12:05:15 2016 +0200
>
>     Don't consider colons to be paragraphs starting chars in strings
>
>     * lisp/emacs-lisp/lisp-mode.el (lisp-fill-paragraph): Don't
>     consider colons to start paragraphs in (doc) strings
>     (bug#7751).
>
> breaks filling doc-strings of defcustoms.  As an example consider the
> defcustom of ‘window-min-height’ in window.el:

I've included a diff below that appears to solve both bug#7751 and this
one, though I can't guarantee that it doesn't blow something else up.
Does anyone have any complaints?

In any case, I think this bug should be solved before 26.1 is released.