Hi Tom,
I replied too soon.
I found this use case which is still broken, in emacs-lisp-mode:
====
(defcustom foo-boolean nil
"Some foo variable.
Some long description that needs to be auto-filled and will span multiple lines."
:group 'foo
:type 'boolean)
=====
With the point anywhere in the doc-string, hit M-q. You will get:
=====
(defcustom foo-boolean nil
"Some foo variable.
Some long description that needs to be auto-filled and will span
multiple lines." :group 'foo :type 'boolean)
=====
But actually this should have happened:
=====
(defcustom foo-boolean nil
"Some foo variable.
Some long description that needs to be auto-filled and will span
multiple lines."
:group 'foo
:type 'boolean)
=====