[enh] display help text for "Other" engines tab in preferences

searx/templates/oscar/preferences.html

@@ -321,6 +321,9 @@
                     <noscript><label>{{ _(categ) }}</label>
                     </noscript>
                     <div class="tab-pane{% if loop.first %} active{% endif %} active_if_nojs" id="tab_engine_{{ categ|replace(' ', '_') }}">
+                        {% if categ == OTHER_CATEGORY %}
+                            <p>{{_('This tab does not show up for search results but you can search the engines listed here via bangs.')}}</p>
+                        {% endif %}
                         <div class="container-fluid">
                         <fieldset>
                           <div class="table-responsive">

searx/templates/simple/preferences.html

@@ -276,6 +276,9 @@
     {{ tabs_open() }}
     {% for categ in categories_as_tabs + [OTHER_CATEGORY] %}
     {{ tab_header('enginetab', 'category' + categ, _(categ)) }}
+    {% if categ == OTHER_CATEGORY %}
+      <p>{{_('This tab does not show up for search results but you can search the engines listed here via bangs.')}}</p>
+    {% endif %}
     <div class="scrollx">
     <table class="striped">
       <tr>