##### 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.

'''Add or remove SELF.NAME to or from GROUP depending on ACTION.
        ACTION can be 'add' or 'remove' otherwise 'remove' is assumed. '''
        rc = 0
        out = ''
        err = ''
        changed = False
        current = set(self._list_user_groups())
        if self.groups is not None:
            target = set(self.groups.split(','))
        else:
            target = set([])
        if self.append is False:
            for remove in current - target:
                (_rc, _err, _out) = self.__modify_group(remove, 'delete')
                rc += rc
                out += _out
                err += _err
                changed = True
        for add in target - current:
            (_rc, _err, _out) = self.__modify_group(add, 'add')
            rc += _rc
            out += _out
            err += _err
            changed = True
        return (rc, err, out, changed)
    def _update_system_user(self):