[fix] add missing no_results.html template to simple theme

searx/templates/simple/messages/no_results.html

@@ -0,0 +1,16 @@
+{% if unresponsive_engines %}
+<div class="alert alert-danger fade in" role="alert">
+    <p><strong>{{ _('Error!') }}</strong> {{ _('Engines cannot retrieve results.') }}</p>
+    <p>
+        {% for engine_name, error_type in unresponsive_engines %}
+        {{ engine_name }} ({{ error_type }}){% if not loop.last %}, {% endif %}
+        {% endfor %}
+    </p>
+    <p><small>{{ _('Please, try again later or find another searx instance.') }}</small></p>
+</div>
+{% else %}
+<div class="alert alert-info fade in" role="alert">
+    <strong>{{ _('Sorry!') }}</strong>
+    {{ _('we didn\'t find any results. Please use another query or search in more categories.') }}
+</div>
+{% endif %}