anchor.diff:              documentation-key
               (partial-completers '(#\Space))
               (separator #\,)
  -            (echo-space t))
  +            (echo-space t)
  +            (printer #'write-token)
  +            (highlighter #'highlight-completion-choice))
     :inherit-from t)
   
   (define-presentation-method presentation-typep (object
  
positive.code:    `(subset-completion ,sequence ,@(and testp `(:test ,test)))
     :name-key name-key
     :documentation-key documentation-key
     :partial-completers partial-completers)
    :options #.+completion-options+)
  
  (define-presentation-type-abbreviation subset-alist (alist
  
negative.code:   (make-presentation-type-specifier `(subset-completion ,elements)
                                      :name-key name-key
                                      :documentation-key documentation-key
                                      :partial-completers partial-completers
                                      :printer printer
                                      :highlighter highlighter)
    :options #.+completion-options+)
  
  (define-presentation-type-abbreviation subset-sequence (sequence
  