anchor.diff:      swap case
   
   *@*::
  -    convert tabs to spaces in current selections, uses the buffer tabstop
  +    convert tabs to spaces in each selection, uses the buffer tabstop
       option or the count parameter for tabstop
   
   *<a-@>*::
  -    convert spaces to tabs in current selections, uses the buffer tabstop
  +    convert spaces to tabs in each selection, uses the buffer tabstop
       option or the count parameter for tabstop
   
   *_*::
  
positive.code:     (See <<expansions#shell-expansions,`:doc expansions shell-expansions`>>)
  
  *!*::
      insert command output before selection. Shell expansions are available,
      (See <<expansions#shell-expansions,`:doc expansions shell-expansions`>>)
  
  *<a-!>*::
      append command output after selection. Shell expansions are available,
      (See <<expansions#shell-expansions,`:doc expansions shell-expansions`>>)
  
  *u*::
  
negative.code: the command behaviour.
  
  For example, *3W* selects 3 consecutive words and *3w* select the third word on
  the right of the end of each selection.
  
  == Disabling Hooks
  
  