Fix wording on results page.

Author: meisterT

webapp/templates/jury/export/results.html.twig

@@ -10,7 +10,7 @@
             <th scope="col">Award</th>
             <th scope="col">Solved problems</th>
             <th scope="col">Total time</th>
-            <th scope="col">Time of last submission</th>
+            <th scope="col">Time of last accepted submission</th>
         </tr>
         </thead>
         <tbody>