anchor.diff:     (download-engine
       :initform :renderer
       :type symbol
  -    :documentation "Select a download engine to use,
  -such as :lisp or :renderer.")
  +    :documentation "Select a download engine to use, such as `:lisp' or
  +`:renderer'.")
      (history-file
       (make-instance 'history-file)
       :type history-file
  
positive.code:    (search-always-auto-complete-p
      t
      :type boolean
      :documentation "Whether auto-completion works even for non-prefixed search.
  Auto-completions come from the default search engine.")
     (keep-search-hints-p
      t
      :type boolean
      :documentation "Whether to keep search hints when the search prompt for the `search-buffer' command is closed.")
     (scroll-distance
      50
      :type integer
  
negative.code:    (horizontal-scroll-distance
      50
      :type integer
      :documentation "Horizontal scroll distance. The distance scroll-left or
  scroll-right will scroll.")
     (current-zoom-ratio
      1.0
      :type float
  