Hide option to clear redis cache

Don't make it tempting to do this

bookwyrm/templates/settings/redis.html

@@ -68,8 +68,15 @@ <h2>{% trans "Outdated cache keys" %}</h2>
 </section>
 
 <section class="block content">
-    <h2>{% trans "Clear Django cache" %}</h2>
-    <div class="box">
+    <h2>{% trans "Advanced" %}</h2>
+    <details class="details-panel box">
+        <summary>
+            <span class="title is-5" role="headind" aria-level="3">
+                {% trans "Clear Django Cache" %}
+            </span>
+            <span class="details-close icon icon-x" aria-hidden="true"></span>
+        </summary>
+
         <p>
         {% blocktrans trimmed %}
         This is <strong>NOT recommended</strong> and should only be used if something has gone very wrong with your cache. All sessions will be cleared and users will be logged out of their accounts.
@@ -86,10 +93,12 @@ <h2>{% trans "Clear Django cache" %}</h2>
             <form name="erase-keys" method="POST" action="{% url 'settings-redis' %}">
                 {% csrf_token %}
                 <input type="hidden" name="erase_cache" value="True">
-                <button type="submit" class="button is-danger">{% trans "Erase cache" %}</button>
+                <div class="control">
+                    <button type="submit" class="button is-danger">{% trans "Erase cache" %}</button>
+                </div>
             </form>
         {% endif %}
-    </div>
+    </details>
 </section>
 
 {% else %}