GH-796 Fix error of questions table

Previously, sorting the questions of a scale by attempt time and then
switching the page via pagination or doing a fulltext search would cause
an error. This is fixed now by using the same column name for the
col_NAME() function as for the sortable column.

classes/output/catscalemanager/questions/questionsdisplay.php

@@ -127,7 +127,7 @@ public function renderquestionstable() {
             'name' => get_string('name', 'core'),
             'model' => get_string('model', 'local_catquiz'),
             'attempts' => get_string('attempts', 'local_catquiz'),
-            'lastattempttime' => get_string('lastattempttime', 'local_catquiz'),
+            'astatlastattempttime' => get_string('lastattempttime', 'local_catquiz'),
             'difficulty' => get_string('difficulty', 'local_catquiz'),
             'discrimination' => get_string('discrimination', 'local_catquiz'),
             'guessing' => get_string('guessing', 'local_catquiz'),

classes/table/catscalequestions_table.php

@@ -196,7 +196,7 @@ public function col_view($values) {
      * @param \stdClass $values
      * @return string
      */
-    public function col_lastattempttime($values) {
+    public function col_astatlastattempttime($values) {
 
         if (intval($values->astatlastattempttime) === 0) {
             return get_string('notyetcalculated', 'local_catquiz');