anchor.diff:  (define-command menu-previous-line (n) ("p")
     (alexandria:when-let ((menu (buffer-value (current-buffer) '%menu)))
       (dotimes (_ n t)
  -      (when (and (menu-use-headline-p menu)
  -                 (>= 2 (line-number-at-point (current-point))))
  +      (when (>= 2 (line-number-at-point (current-point)))
           (return))
         (line-offset (current-point) -1))))
   
  
positive.code:     (unless (menu-previous-line 1)
        (return))
      (unmark-line (current-point))))
  
  (defun marked-menu-items (point indicator)
    (or (loop :for ov :in (buffer-value point 'mark-overlays)
              :collect (menu-property-at (overlay-start ov) indicator))
        (list (menu-property-at point indicator))))
  
negative.code:            :menu-item
             :append-menu
             :append-menu-item
             :display-menu))
  (in-package :lem.menu-mode)
  
  (define-attribute head-line-attribute
  