Formio: How can I add a tooltip to a html element?

I am using the formio renderer to display a form in an angular app. I pass a json-object to the formio directive. Now I am trying to place at tooltip to a component. To a textfield it is no problem:

        {
            "label": "Text Field",
            "tooltip": "This is a tooltip",
            "tableView": true,
            "key": "textField",
            "type": "textfield",
            "input": true
        }

But I don't know what is the proper way to do it on a html-element or a header for a table. My purpose is to have tooltips on the header elements of a table. As work around for a html element I tried this. But I wonder if there is a better way.

       {
            "content": "a little text"+ " <i class="fa fa-question-circle text-muted" ref="tooltip"></i><span class="tooltip"</span>',
            "type": "htmlelement",
            "tooltip": "myhtml tooltip"
        }