I don't know about these strings
"Groupings are a standard feature in later Moodle versions"
What exactly is a later Moodle version? 1.9? 2.0?
$string['enablegroupings'] = 'Enable groupings and Available for group members only';
Should this be the below?
$string['enablegroupings'] = 'Enable groupings and \'Available for group members only\'';
Also, if people are confused about what groupings are as is stated in the bug report these changes make no attempt to help with that. It still assumes the user knows what a grouping is.