##### 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')
```
tags.add(tag.strip())
            options.tags = list(tags)
        
        if hasattr(options, 'skip_tags') and options.skip_tags:
            skip_tags = set()
            for tag_set in options.skip_tags:
                for tag in tag_set.split(u','):
                    skip_tags.add(tag.strip())
            options.skip_tags = list(skip_tags)
        
        if hasattr(options, 'inventory') and not self.SKIP_INVENTORY_DEFAULTS:
            if options.inventory:
                
                if isinstance(options.inventory, string_types):
                    options.inventory = [options.inventory]
                
                options.inventory = [unfrackpath(opt, follow=False) if ',' not in opt else opt for opt in options.inventory]
            else:
                options.inventory = C.DEFAULT_HOST_LIST
        
        
        
        if self.parser.prog in ['ansible-galaxy', 'ansible-vault'] and not options.verbosity:
            verbosity_arg = next(iter([arg for arg in self.args if arg.startswith('-v')]), None)
            if verbosity_arg:
                display.deprecated("Setting verbosity before the arg sub command is deprecated, set the verbosity "
                                   "after the sub command", "2.13")
                options.verbosity = verbosity_arg.count('v')
        return options
    def parse(self):