Fix Clang compile by adding effectless command to variable studentIdx

src/data/nodes/dynexite_exam.cpp

@@ -280,6 +280,9 @@ void DynexiteExam::insertData(
     // Ignore header line, ignore empty, non-attendant students
     for (auto studentIdx = 0; const auto &line : c.data | std::views::drop(1)) {
 
+        // This statement does nothing but avoids -Wunused-but-set-variable Error with Clang
+        (void)studentIdx;
+
         // Skip non-attending students
         if (line[0].isEmpty())
             continue;