code: public CmdLineAction onOption(BiConsumer<@NonNull String, @NonNull String> action) {
  		OptionCmdLineAction optionAction = new OptionCmdLineAction(action);
  
  		this.optionActions.add(optionAction);
  		return optionAction;
  	}
docs: Add a {@linkplain CmdLineAction} for option argument ({@code e.g. --option value}) processing.
  
  @param action The {@linkplain BiConsumer} to invoke with the argument and option string.
  @return The created {@linkplain CmdLineAction}.