##### SUMMARY
The documentation of the module *user* / parameter *shell* states:

https://github.com/ansible/ansible/blob/8edad83ae029d7838a6d6347576d2ddbcce12ad0/lib/ansible/modules/system/user.py#L79

But there are no (shell specific) notes.
##### ISSUE TYPE
- Documentation Report

##### COMPONENT NAME
user / docs

##### ANSIBLE VERSION
devel branch

##### CONFIGURATION
N/A

##### OS / ENVIRONMENT
N/A

##### ADDITIONAL INFORMATION
Either remove the sentence or provide some information in the notes section.

cmd.append('-k')
                cmd.append(self.skeleton)
        if self.shell is not None:
            cmd.append('-s')
            cmd.append(self.shell)
        if self.login_class is not None:
            cmd.append('-L')
            cmd.append(self.login_class)
        if self.expires is not None:
            cmd.append('-e')
            if self.expires < time.gmtime(0):
                cmd.append('0')
            else:
                cmd.append(str(calendar.timegm(self.expires)))
        
        
        (rc, out, err) = self.execute_command(cmd)
        if rc is not None and rc != 0:
            self.module.fail_json(name=self.name, msg=err, rc=rc)
        
        if self.password is not None:
            cmd = [
                self.module.get_bin_path('chpass', True),
                '-p',
                self.password,
                self.name
            ]
            return self.execute_command(cmd)
        return (rc, out, err)
    def modify_user(self):