### Summary

The [list of builtin modules](https://docs.ansible.com/ansible/latest/collections/ansible/builtin/index.html) shows two modules with similar names and identical descriptions:

> [systemd module](https://docs.ansible.com/ansible/latest/collections/ansible/builtin/systemd_module.html#ansible-collections-ansible-builtin-systemd-module) – Manage systemd units
> [systemd_service module](https://docs.ansible.com/ansible/latest/collections/ansible/builtin/systemd_service_module.html#ansible-collections-ansible-builtin-systemd-service-module) – Manage systemd units

My guess was that `systemd_service` would manage services running with systemd, and `systemd` would manage `systemd` itself. But the description is identical. The synopsis is identical. The arguments and examples appear identical.

As a user, I expect that if one module has two names, the documentation would state that one is an alias.

Looking at [the code](https://github.com/ansible/ansible/blob/devel/lib/ansible/modules/systemd.py) I see that `systemd` is symlinked to `systemd_service.py`.

Please modify the documentation to state that one is an alias of the other, and they are identical.


### Issue Type

Documentation Report

### Component Name

systemd_service

### Ansible Version

```console
N/A
```


### Configuration

```console
N/A
```


### OS / Environment

N/A

### Additional Information

For context, my objective is to create a service file, and then enable+start it. I was hoping that there would be one module to do that. But then I saw there are two similar ones, and I thought one would create the .service file, and the other would load+run it. But that doesn't appear to be the case either.

### Code of Conduct

- [X] I agree to follow the Ansible Code of Conduct
return service_status['ActiveState'] in set(['active', 'activating'])
def is_deactivating_service(service_status):
    return service_status['ActiveState'] in set(['deactivating'])
def request_was_ignored(out):
    return '=' not in out and ('ignoring request' in out or 'ignoring command' in out)
def parse_systemctl_show(lines):
    
    
    
    
    
    
    
    
    #
    
    
    
    parsed = {}
    multival = []
    k = None
    for line in lines:
        if k is None:
            if '=' in line:
                k, v = line.split('=', 1)
                if k.startswith('Exec') and v.lstrip().startswith('{'):
                    if not v.rstrip().endswith('}'):
                        multival.append(v)
                        continue