Mark separate library as highly experimental

cps/templates/config_db.html

@@ -18,7 +18,7 @@
       </div>
       <div class="form-group required">
         <input type="checkbox" id="config_calibre_split" name="config_calibre_split" data-control="split_settings" data-t ="{{ config.config_calibre_split_dir  }}" {% if config.config_calibre_split %}checked{% endif %} >
-        <label for="config_calibre_split">{{_('Separate Book files from Library')}}</label>
+        <label for="config_calibre_split">{{_('Separate Book files from Library (Highly experimental, might not work at all)')}}</label>
       </div>
       <div data-related="split_settings">
        <div class="form-group required input-group">