# Append raw HTML to element
	#
	#     var p = new HTMLTag("p")
	#     p.append("Hello")
	#     p.add_raw_html("<bla/>foo")
	#     assert p.write_to_string   == "<p>Hello<bla/>foo</p>"
	#
	# Note: the HTML in insered as it, no verification is done.
	fun add_raw_html(txt: String): HTMLTag do
		add(new HTMLRaw("", txt))
		return self
	end