# Append `element` and the end of the template then append a "\n".
	#
	#     var t = new Template
	#     t.addn("1")
	#     t.addn("2")
	#     assert t.write_to_string == "1\n2\n"
	fun addn(element: Writable) do
		add element
		add "\n"
	end