(set-marker sig-end-marker (point-max))
(overlay-put (make-overlay sig-start-marker sig-end-marker) 'face 'message-cited-text)
(notmuch-wash-region-to-button
(set-marker sig-end-marker (point-max))
(overlay-put (make-overlay sig-start-marker sig-end-marker) 'face 'message-cited-text)
(notmuch-wash-region-to-button