[themes] add hyperlink to searx instances list in error message

closes: #2383

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/templates/oscar/messages/no_results.html

@@ -7,7 +7,7 @@
         {{ engine_name }} ({{ error_type }}){% if not loop.last %}, {% endif %}
         {% endfor %}
     </p>
-    <p><small>{{ _('Please, try again later or find another searx instance.') }}</small></p>
+    <p><small>{{ _('Please, try again later or find another searx instance.') }} (<a href="{{ brand.PUBLIC_INSTANCES }}">{{ _('Public instances') }}</a>)</small></p>
 </div>
 {% else %}
 <div class="alert alert-info fade in" role="alert">

searx/templates/simple/messages/no_results.html

@@ -7,7 +7,7 @@
     {{ engine_name }} ({{ error_type }}){% if not loop.last %}, {% endif %}
     {% endfor %}
   </p>
-  <p><small>{{ _('Please, try again later or find another searx instance.') }}</small></p>
+  <p><small>{{ _('Please, try again later or find another searx instance.') }} (<a href="{{ brand.PUBLIC_INSTANCES }}">{{ _('Public instances') }}</a>) </small></p>
 </div>
 {% else %}
 <div class="dialog-error" role="alert">