anchor.diff:     - Indentation
      - Piping each selection to external filter
    * Simple interaction with external programs
  + * Automatic contextual help
  + * Automatic as you type completion
    * Macros
    * Hooks
    * Syntax Highlighting
  
positive.code:  * +-hidden+: do not show the command in command name completions
  
  Using shell expansion permits to define complex commands or to access
  kakoune state:
  
  ------------------------------------------------------
  :def print_selection %{ echo %sh{ ${kak_selection} } }
  
negative.code: syntax and is evaluated only when needed.
  for example: %sh{ ls } is replaced with the output of the ls command.
  
  Some of Kakoune state is available through environment variables:
  
   * +kak_selection+: content of the main selection
   * +kak_selections+: content of the selection separated by colons, colons in
  