##### 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.

if groups_need_mod:
                cmd.append('-G')
                new_groups = groups
                if self.append:
                    new_groups = groups | set(current_groups)
                cmd.append(','.join(new_groups))
        if self.expires is not None:
            current_expires = int(self.user_password()[1])
            
            
            if self.expires <= time.gmtime(0):
                if current_expires > 0:
                    cmd.append('-e')
                    cmd.append('0')
            else:
                
                current_expire_date = time.gmtime(current_expires)
                
                if current_expires <= 0 or current_expire_date[:3] != self.expires[:3]:
                    cmd.append('-e')
                    cmd.append(str(calendar.timegm(self.expires)))
        
        if cmd_len != len(cmd):
            (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)
        else:
            (rc, out, err) = (None, '', '')
        
        if self.update_password == 'always' and self.password is not None and info[1] != self.password: