anchor.diff:  
   existing highlighters are:
   
  -* *highlight_selections*: used to make current selection visible
  -* *expand_tabs*: expand tabs to next 8 multiple column (to make configurable)
  -* *number_lines*: show line numbers
  -* *regex*: highlight a regex, takes 3 parameters <regex> <fg_color> <bg_color>
  -* *group*: highlighter group, containing other highlighters. takes one
  -           parameter, <group_name>. useful when multiple highlighters work
  -           together and need to be removed as one. Adding and removing from
  -           a group can be done using
  -           :addhl -group <group> <highlighter_name> <highlighter_parameters...>
  -           :rmhl  -group <group> <highlighter_name>
  + * *highlight_selections*: used to make current selection visible
  + * *expand_tabs*: expand tabs to next 8 multiple column (to make configurable)
  + * *number_lines*: show line numbers
  + * *group*: highlighter group, containing other highlighters. takes one
  +            parameter, <group_name>. useful when multiple highlighters work
  +            together and need to be removed as one. Adding and removing from
  +            a group can be done using
  +            :addhl -group <group> <highlighter_name> <highlighter_parameters...>
  +            :rmhl  -group <group> <highlighter_name>
  + * *regex*: highlight a regex, takes the regex as first parameter, followed by
  +            any number of color spec parameters.
  +            color spec format is: <capture_id>:<fg_color>[,<bg_color>]
  +            For example:
  +            :addhl regex //(\h+TODO:)?[^\n]+ 0:cyan 1:yellow,red
  +            will highlight C++ style comments in cyan, with an eventual
  +            'TODO:' in yellow on red background.
   
   Filters
   -------
  
positive.code: for example, _3W_ selects 3 consecutive words and _3w_ select the third word on
  the right of selection end.
  
  * _space_: when used with count, keep only the counth selection
  * _alt-space_: when used with count, remove the counth selection
  
  Changes
  -------
  
negative.code: Using alt-i and alt-a, you can select some text object, the starting
  point is always the last character of the selection.
  
   * _b_, _(_ or _)_: select the enclosing parenthesis
   * _B_, _{_ or _}_: select the enclosing {} block
   * _[_ or _]_: select the enclosing [] block
   * _<_ or _>_: select the enclosing <> block
   * w: select the whole word
   * W: select the whole WORD
  
  When it makes sense, _alt-i_ selects the inner object and alt-a the whole
  object. For example _alt-i_ ( will only select the inside of the parenthesis,
  