Move tbody tag out of for loop in DBtable's index-table

Signed-off-by: Sebastian Walther <swalther@complex-it.de>

templates/table/structure/display_structure.twig

@@ -467,8 +467,8 @@
               </tr>
             </thead>
 
+          <tbody class="row_span">
             {% for index in indexes %}
-              <tbody class="row_span">
                 {% set columns_count = index.getColumnCount() %}
                 <tr class="noclick">
                 <td rowspan="{{ columns_count }}" class="edit_index d-print-none ajax">
@@ -534,8 +534,8 @@
                   {% endif %}
                   </tr>
                 {% endfor %}
-              </tbody>
-            {% endfor %}
+              {% endfor %}
+            </tbody>
           </table>
         </div>
       {% else %}