code: @Nonnull
    public TypeaheadDataset setFooter (@Nullable final String sFooterHTML)
    {
      return setFooter (StringHelper.hasText (sFooterHTML) ? JSExpr.lit (sFooterHTML) : (IJSExpression) null);
    }
docs: The footer rendered after suggestions in the dropdown menu. Can be either a
  DOM element or HTML.
  
  @param sFooterHTML
  The footer to use. May be <code>null</code> or empty.
  @return this