anchor.diff:      an option of this type, its lines gets updated according to all the
       buffer modifications that happened since its timestamp.
       See <<highlighters#specs-highlighters,`:doc highlighters specs-highlighters`>>)
  +    `set -add` appends the new spec to the list
   
   *completions*::
       a `:` separated list of `<text>|<docstring>|<menu text>`
  
positive.code: Options can be modified using the `set-option` command:
  
  ---------------------------------
  set-option <scope> <name> <value>
  ---------------------------------
  
  <scope> can be *global*, *buffer*, *window* or *current* (See
  <<scopes#,`:doc scopes`>>). *current* relate to the narrowest scope in
  which the option is already set.
  
  [[unset-option]]
  Options values can be unset in a specific scope with the `unset-option`
  
negative.code:     is not a valid regex
  
  *coord*::
      a line, column pair (separated by a comma)
  
  *<type>-list*::
      a list, elements are separated by a colon (:) if an element needs
      to contain a colon, it can be escaped with a backslash.
      `set -add` appends the new element to the list
  
  *range-specs*::
      a `:` separated list of a pair of a buffer range (`<begin
  