code: @Nonnull
    public TypeaheadDataset setFooter (@Nullable final IHCNode aFooter)
    {
      return setFooter (aFooter != null ? HCRenderer.getAsHTMLStringWithoutNamespaces (aFooter) : (String) null);
    }
docs: The footer rendered after suggestions in the dropdown menu. Can be either a
  DOM element or HTML.
  
  @param aFooter
  The footer to use. May be <code>null</code>.
  @return this