removing potentially confusing duplicate unused lang string

htdocs/lang/en.utf8/view.php

@@ -98,7 +98,6 @@ $string['feedback'] = 'Feedback';
 $string['feedbackattachdirname'] = 'assessmentfiles';
 $string['feedbackattachdirdesc'] = 'Files attached to view assessments';
 $string['feedbackattachmessage'] = 'The attached file has been added to your %s folder';
-$string['feedbackmadeprivate'] = 'Feedback changed to private';
 $string['feedbackonthisartefactwillbeprivate'] = 'Feedback on this artefact will only be visible to the owner.';
 $string['feedbackonviewbytutorofgroup'] = 'Feedback on %s by %s of %s';
 $string['feedbacksubmitted'] = 'Feedback submitted';