Correct num_plurals in zen mode

Signed-off-by: Michal Čihař <michal@cihar.com>

weblate/html/zen-units.html

@@ -17,7 +17,7 @@
 </tr>
 <tr id="row-source-{{ item.unit.checksum }}">
 <td></td>
-<td colspan="2" class="translatetext">{% format_translation item.unit.source search_match=search_query %}</td>
+<td colspan="2" class="translatetext">{% format_translation item.unit.source search_match=search_query num_plurals=unit.translation.language.nplurals %}</td>
 </tr>
 <tr id="row-edit-{{ item.unit.checksum }}">
 <td>