### Summary

The [`filename` parameter docs](https://docs.ansible.com/ansible/latest/collections/ansible/builtin/apt_repository_module.html#parameter-filename) don't give enough info to tell how the file name is generated.

I believe my `repo: deb https://packagecloud.io/linz/prod/ubuntu/ {{ ansible_distribution_release }} main` is hanging indefinitely ~~, and I suspect this has something to do with the file name being a duplicate, resulting in a background prompt which is never printed or dismissed, but it's hard to tell based on the [code](https://github.com/ansible/ansible/blob/f3be331c9cb2f2c6edeb0bdf28a1e8a9681d727c/lib/ansible/modules/apt_repository.py#L235-L258)~~ (Based on copying the code into a Python interpreter it looks like the generated file name is `packagecloud_io_linz_prod_ubuntu.list`, which looks fine.).

### Issue Type

Documentation Report

### Component Name

lib/ansible/modules/apt_repository.py

### 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
for filename, sources in list(self.files.items()):
            if sources:
                d, fn = os.path.split(filename)
                try:
                    os.makedirs(d)
                except OSError as ex:
                    if not os.path.isdir(d):
                        self.module.fail_json("Failed to create directory %s: %s" % (d, to_native(ex)))
                try:
                    fd, tmp_path = tempfile.mkstemp(prefix=".%s-" % fn, dir=d)
                except (OSError, IOError) as e:
                    self.module.fail_json(msg='Unable to create temp file at "%s" for apt source: %s' % (d, to_native(e)))
                f = os.fdopen(fd, 'w')
                for n, valid, enabled, source, comment in sources:
                    chunks = []
                    if not enabled:
                        chunks.append('# ')
                    chunks.append(source)
                    if comment:
                        chunks.append(' # ')
                        chunks.append(comment)
                    chunks.append('\n')
                    line = ''.join(chunks)
                    try: