### Summary

The documentation about how systems determine the default shell is confusing.

At the [shell parameter](https://docs.ansible.com/ansible/latest/collections/ansible/builtin/user_module.html#parameter-shell) is written: "See notes for details on how other operating systems determine the default shell by the underlying tool."

The [Notes section](https://docs.ansible.com/ansible/latest/collections/ansible/builtin/user_module.html#notes) does not contain "details on how other operating systems determine the default shell".

If I read this, I would expect to find something along the lines of "On FreeBSD, the default shell is set by `dscl`". 

Instead, it contains notes on which underlying tools are used by the module to create, modify and remove accounts. This is only helpful if the reader is already aware of the fact that these underlying tools _also_ set the default shell.

Furthermore, since the notes at the shell parameter explicitly spell out what the default shell on macOS is, the user has a reasonable expectation to find similarly worded notes for other operating systems in the Notes.

A possible solution: replace "See notes for details on how other operating systems determine the default shell by the underlying tool." with "On other operating systems, the default shell is determined by the underlying tool invoked by this module. See Notes for a per platform list of invoked tools."

### Issue Type

Documentation Report

### Component Name

lib/ansible/modules/user.py

### Ansible Version

```console
N/a
```


### Configuration

```console
N/a
```


### OS / Environment

N/a

### Additional Information

Previous bug report and attempted (but IMO inadequate) fix here: https://github.com/ansible/ansible/issues/59796. 

### Code of Conduct

- [X] I agree to follow the Ansible Code of Conduct
- If this is a relative filename then it will be relative to the user's home directory.
            - This parameter defaults to V(.ssh/id_rsa).
        type: path
        version_added: "0.9"
    ssh_key_comment:
        description:
            - Optionally define the comment for the SSH key.
        type: str
        default: ansible-generated on $HOSTNAME
        version_added: "0.9"
    ssh_key_passphrase:
        description:
            - Set a passphrase for the SSH key.
            - If no passphrase is provided, the SSH key will default to having no passphrase.
        type: str
        version_added: "0.9"
    update_password:
        description:
            - V(always) will update passwords if they differ.
            - V(on_create) will only set the password for newly created users.
        type: str
        choices: [ always, on_create ]
        default: always
        version_added: "1.3"
    expires:
        description:
            - An expiry time for the user in epoch, it will be ignored on platforms that do not support this.
            - Currently supported on GNU/Linux, FreeBSD, and DragonFlyBSD.
            - Since Ansible 2.6 you can remove the expiry time by specifying a negative value.
              Currently supported on GNU/Linux and FreeBSD.