code: private CommandContainer<CI> getCommand(ParsedLine aeshLine, String line) throws CommandNotFoundException {
          return getCommand(aeshLine.words().get(0).word(), line);
      }
docs: try to return the command in the given registry if the given registry do not find the command, check if we have a
  internal registry and if its there.
  
  @param aeshLine parsed command line
  @param line command line
  @return command
  @throws CommandNotFoundException