help for return type.

[outscale-mgo]

--help ReadVms show all params arguments help, but we don't have return types explaines.
Adding return type help ine the --help, could e slightly to verbose, so I guess we need either a new options, (--help-return) or a new arguments to --help (--help --all ReadVms, --help --in ReadVms, --help --out ReadVms --help --brief ReadVms, --help --default ReadVms)