##### SUMMARY
With the introduction of `Collection` mechanism using the `ansible-galaxy` CLI, the command and sub command help texts should be reflecting the new feature. The CLI currently validates the `collection` sub-command but the help text is still saying `role` is the only valid sub-command.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
`ansible-galaxy`

##### ANSIBLE VERSION
```
ansible 2.9.7
  config file = /etc/ansible/ansible.cfg
  configured module search path = ['/home/dvercill/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /home/dvercill/.local/lib/python3.8/site-packages/ansible
  executable location = /home/dvercill/.local/bin/ansible
  python version = 3.8.2 (default, Feb 28 2020, 00:00:00) [GCC 10.0.1 20200216 (Red Hat 10.0.1-0.8)]
```

##### CONFIGURATION
N/A

##### OS / ENVIRONMENT
Fedora Workstation 32 beta

##### STEPS TO REPRODUCE
```
$ ansible-galaxy doesnotexist
usage: ansible-galaxy role [-h] ROLE_ACTION ...
ansible-galaxy role: error: argument ROLE_ACTION: invalid choice: 'doesnotexist' (choose from 'init', 'remove', 'delete', 'list', 'search', 'import', 'setup', 'login', 'info', 'install')
```
import getpass
import os
import re
import subprocess
import sys
from abc import ABCMeta, abstractmethod
from ansible.cli.arguments import option_helpers as opt_help
from ansible import constants as C
from ansible import context
from ansible.errors import AnsibleError
from ansible.inventory.manager import InventoryManager
from ansible.module_utils.six import with_metaclass, string_types
from ansible.module_utils._text import to_bytes, to_text
from ansible.parsing.dataloader import DataLoader
from ansible.parsing.vault import PromptVaultSecret, get_file_vault_secret
from ansible.plugins.loader import add_all_plugin_dirs
from ansible.release import __version__
from ansible.utils.collection_loader import AnsibleCollectionConfig
from ansible.utils.collection_loader._collection_finder import _get_collection_name_from_path
from ansible.utils.display import Display
from ansible.utils.path import unfrackpath
from ansible.utils.unsafe_proxy import to_unsafe_text
from ansible.vars.manager import VariableManager
try:
    import argcomplete
    HAS_ARGCOMPLETE = True
except ImportError:
    HAS_ARGCOMPLETE = False
display = Display()
class CLI(with_metaclass(ABCMeta, object)):