### Summary

https://docs.ansible.com/ansible/latest/collections/ansible/builtin/mandatory_filter.html makes no mention of the `msg` argument that was introduced in 0e7e3c0ae89a70c386168827b0c9defb956bee7e

### Issue Type

Documentation Report

### Component Name

lib/ansible/plugins/filter/mandatory.yml

### Ansible Version

```console
n/a
```


### Configuration

```console
n/a
```


### OS / Environment

n/a

### Additional Information

n/a

### Code of Conduct

- [X] I agree to follow the Ansible Code of Conduct
prepostfix = style_params['decoration']
    
    p = {
        'newline': '\n',
        'beginning': '',
        'prefix': (prepostfix).rstrip(),
        'prefix_count': 1,
        'decoration': '',
        'postfix': (prepostfix).rstrip(),
        'postfix_count': 1,
        'end': ''
    }
    
    p.update(style_params)
    p.update(kw)
    
    str_beginning = ''
    if p['beginning']:
        str_beginning = "%s%s" % (p['beginning'], p['newline'])
    str_prefix = ''
    if p['prefix']:
        if p['prefix'] != p['newline']:
            str_prefix = str(
                "%s%s" % (p['prefix'], p['newline'])) * int(p['prefix_count'])
        else:
            str_prefix = str(
                "%s" % (p['newline'])) * int(p['prefix_count'])
    str_text = ("%s%s" % (
        p['decoration'],