MassRemovePage: Add Remove Explenation

gadget/gadget_cribjs_page_mass_remove.html

@@ -18,6 +18,7 @@
     <div class="nav_content mass_remove container">
       <form class="crib-mass-remove">
         <h3>Mass removal</h3>
+        <p>Enter the list of URLs with one URL per line.<br/> <span>&#x26A0;&#xFE0F;</span> <b>It will remove definitly the content from this URL.</b></p>
         <div class="form-group">
           <textarea name="mass-remove-list" cols="35" wrap="soft" class="form-control"></textarea>
         </div>