anchor.diff:  -------
   
   Filters can be installed to interact with buffer modifications. They can be
  -added or removed with :addfilter <filter_name> <filter_parameters...> and
  +added or removed with
  +-----------------------------------------------
  +:addfilter <filter_name> <filter_parameters...>
  +-----------------------------------------------
  +and
  +---------------------
   :rmfilter <filter_id>
  +---------------------
   
   exisiting filters are:
   
  - * *preserve_indent*: insert previous line indent when inserting a newline
  - * *cleanup_whitespaces*: remove trailing whitespaces on the previous line
  + * +preserve_indent+: insert previous line indent when inserting a newline
  + * +cleanup_whitespaces+: remove trailing whitespaces on the previous line
                             when inserting an end-of-line.
  - * *expand_tabulations*: insert spaces instead of tab characters
  - * *group*: same as highlighters group
  + * +expand_tabulations+: insert spaces instead of tab characters
  + * +group+: same as highlighters group
   
   Hooks
   -----
   
   commands can be registred to be executed when certain events arise.
   to register a hook, use the hook command.
  -
  +------------------------------------------------------
   :hook <scope> <hook_name> <filtering_regex> <commands>
  -
  +------------------------------------------------------
   <scope> can be either global, buffer or window, the scope are hierarchical,
   meaning that a Window calling a hook will execute it's own, the buffer ones
   and the global ones.
  
positive.code: 
  for example, to automatically use line numbering with .cc files,
  use the following command:
  
  :hook global WinCreate .*\.cc %{ addhl number_lines }
  
  Shell expansion
  ---------------
  
negative.code: Basic Commands
  --------------
  
  Commands are entered using +:+.
  
   * +e[dit] <filename> [<line> [<column>]]+: open buffer on file, go to given
       line and column. If file is already opened, just switch to this file.
       use edit! to force reloading.
   * +w[rite] [<filename>]+: write buffer to <filename> or use it's name if
        filename is not given.
   * +q[uit]+: exit Kakoune, use quit! to force quitting even if there is some
        unsaved buffers remaining.
   * +wq+: write current buffer and quit
   * +b[uffer] <name>+: switch to buffer <name>
   * +d[el]b[uf] [<name>]+: delete the buffer <name>
   * +source <filename>+: execute commands in <filename>
   * +runtime <filename>+: execute commands in <filename>, <filename>
        is relative to kak executable path.
   * +exec <keys>+: execute <keys> as if pressed in normal mode.
   * +echo <text>+: show <text> in status line
   * +set[bwg] <option> <value>+: set <option> to <value> in *b*uffer, *w*indow
        or *g*lobal scope.
  
  String syntax
  