### Summary

Running `ansible-doc -l` generates 430 deprecation warnings on stderr before printing anything to stdout.
```
[DEPRECATION WARNING]: amazon.aws.aws_az_facts has been deprecated.
aws_az_facts was renamed in Ansible 2.9 to aws_az_info. Please update your
tasks. This feature will be removed from amazon.aws in a release after
2022-06-01. Deprecation warnings can be disabled by setting
deprecation_warnings=False in ansible.cfg.

[DEPRECATION WARNING]: amazon.aws.aws_caller_facts has been deprecated.
aws_caller_facts was renamed in Ansible 2.9 to aws_caller_info. Please update
your tasks. This feature will be removed from amazon.aws in a release after
2021-12-01. Deprecation warnings can be disabled by setting
deprecation_warnings=False in ansible.cfg.
...
```

### Issue Type

Bug Report

### Component Name

ansible-doc

### Ansible Version

```console
$ ansible-doc --version

ansible-doc 2.10.6
  config file = None
  configured module search path = [u'/home/charleshowes/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/local/lib/python2.7/dist-packages/ansible
  executable location = /usr/local/bin/ansible-doc
  python version = 2.7.17 (default, Sep 30 2020, 13:38:04) [GCC 7.5.0]
```


### Configuration

```console
$ ansible-config dump --only-changed
(no output)
```


### OS / Environment

Ubuntu 18.04

### Steps to Reproduce

<!--- Paste example playbooks or commands between quotes below -->
```shell (paste below)
ansible-doc -l
```


### Expected Results

I expected to see a list of available plugins, and was shocked to have pages and pages of warnings.

### Actual Results

```console
$ ansible-doc -l 2>&1 | head

[DEPRECATION WARNING]: amazon.aws.aws_az_facts has been deprecated. 
aws_az_facts was renamed in Ansible 2.9 to aws_az_info. Please update your 
tasks. This feature will be removed from amazon.aws in a release after 
2022-06-01. Deprecation warnings can be disabled by setting 
deprecation_warnings=False in ansible.cfg.
[DEPRECATION WARNING]: amazon.aws.aws_caller_facts has been deprecated. 
aws_caller_facts was renamed in Ansible 2.9 to aws_caller_info. Please update 
your tasks. This feature will be removed from amazon.aws in a release after 
2021-12-01. Deprecation warnings can be disabled by setting 
deprecation_warnings=False in ansible.cfg.

$ ansible-doc -l 2>&1 | grep -c 'DEPRECATION WARNING'

430
```


### Code of Conduct

- [X] I agree to follow the Ansible Code of Conduct
plugin_load_context = self._find_plugin_legacy(name.replace('ansible.legacy.', '', 1),
                                                                       plugin_load_context, ignore_deprecated, check_aliases, suffix)
                    else:
                        
                        plugin_load_context = self._find_fq_plugin(candidate_name, suffix, plugin_load_context=plugin_load_context)
                        
                        
                        
                        
                        
                        if plugin_load_context.resolved and candidate_name not in plugin_load_context.redirect_list:
                            plugin_load_context.redirect_list.append(candidate_name)
                    if plugin_load_context.resolved or plugin_load_context.pending_redirect:  
                        return plugin_load_context
                except (AnsiblePluginRemovedError, AnsiblePluginCircularRedirect, AnsibleCollectionUnsupportedVersionError):
                    
                    raise
                except ImportError as ie:
                    plugin_load_context.import_error_list.append(ie)
                except Exception as ex:
                    
                    plugin_load_context.error_list.append(to_native(ex))
            if plugin_load_context.error_list:
                display.debug(msg='plugin lookup for {0} failed; errors: {1}'.format(name, '; '.join(plugin_load_context.error_list)))
            plugin_load_context.exit_reason = 'no matches found for {0}'.format(name)
            return plugin_load_context
        
        return self._find_plugin_legacy(name, plugin_load_context, ignore_deprecated, check_aliases, suffix)
    def _find_plugin_legacy(self, name, plugin_load_context, ignore_deprecated=False, check_aliases=False, suffix=None):