Add details to the Manage Subscription description [MAILPOET-853]

views/settings/basics.html

@@ -217,6 +217,8 @@
         </label>
         <p class="description">
           <%= __('When your subscribers click the "Manage your subscription" link, they will be directed to this page.') %>
+          <br />
+          <%= __('If you want to use a custom Subscription page, simply paste this shortcode on to a WordPress page: [mailpoet_manage_subscription]') %>
         </p>
       </th>
       <td>