##### SUMMARY
If a module sets `add_file_common_args=True` when calling `AnsibleModule`, all elements from [FILE_COMMON_ARGUMENTS](https://github.com/ansible/ansible/blob/e9d29b1fe4285d90d7a4506b80260a9e24c3bcea/lib/ansible/module_utils/basic.py#L229-L257) are included in the argument spec. The [files document fragment](https://github.com/ansible/ansible/blob/e9d29b1fe4285d90d7a4506b80260a9e24c3bcea/lib/ansible/plugins/doc_fragments/files.py#L15-L80) only documents a subset of them, though. Missing are:
 - src
 - follow
 - force
 - content
 - backup
 - remote_src
 - regexp
 - delimiter
 - directory_mode

Most module authors using `add_file_common_args=True` are probably not aware that their modules have these options as well.

I don't think these extra options should be added by default if `add_file_common_args=True` is specified.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
lib/ansible/module_utils/basic.py

##### ANSIBLE VERSION
```
devel
```

argument_spec = url_argument_spec()
    argument_spec.update(
        dest=dict(type='path'),
        url_username=dict(type='str', aliases=['user']),
        url_password=dict(type='str', aliases=['password'], no_log=True),
        body=dict(type='raw'),
        body_format=dict(type='str', default='raw', choices=['form-urlencoded', 'json', 'raw']),
        src=dict(type='path'),
        method=dict(type='str', default='GET'),
        return_content=dict(type='bool', default=False),
        follow_redirects=dict(type='str', default='safe', choices=['all', 'no', 'none', 'safe', 'urllib2', 'yes']),
        creates=dict(type='path'),
        removes=dict(type='path'),
        status_code=dict(type='list', default=[200]),
        timeout=dict(type='int', default=30),
        headers=dict(type='dict', default={}),
        unix_socket=dict(type='path'),