cinder group-show --list-volume args incorrect.

cinder group-show with an option to list the volumes was introduced with https://review.openstack.org/#/c/432179/, however it's arguments are inconsistent with the rest of the client group commands.

# cinder help group-show
usage: cinder group-show [--list-volume [<False|True>]] <group>

Shows details of a group.

Positional arguments:
  <group> Name or ID of a group.

Optional arguments:
  --list-volume [<False|True>]
                        Shows volumes included in the group. (Supported by API
                        version 3.25 and later)

There are two issues:
1. --list-volume should be --list-volumes as other commands use --<cmd>-volumes

# cinder help group-delete
usage: cinder group-delete [--delete-volumes] <group> [<group> ...]

Removes one or more groups.

Positional arguments:
  <group> Name or ID of one or more groups to be deleted.

Optional arguments:
  --delete-volumes Allows or disallows groups to be deleted if they are not
                    empty. If the group is empty, it can be deleted without
                    the delete-volumes flag. If the group is not empty, the
                    delete-volumes flag is required for it to be deleted. If
                    True, all volumes in the group will also be deleted.

# cinder help group-update
usage: cinder group-update [--name <name>] [--description <description>]
                           [--add-volumes <uuid1,uuid2,......>]
                           [--remove-volumes <uuid3,uuid4,......>]
                           <group>

Updates a group.

Positional arguments:
  <group> Name or ID of a group.

Optional arguments:
  --name <name> New name for group. Default=None.
  --description <description>
                        New description for group. Default=None.
  --add-volumes <uuid1,uuid2,......>
                        UUID of one or more volumes to be added to the group,
                        separated by commas. Default=None.
  --remove-volumes <uuid3,uuid4,......>
                        UUID of one or more volumes to be removed from the
                        group, separated by commas. Default=None.

2. there is no need for a False|True argument, the option being present is already a call for True.