title: React PropTypes DOM element?
body: <p>How do I mark a property as having to be a DOM element?</p>
  
  <p><a href="https://facebook.github.io/react/docs/reusable-components.html" rel="noreferrer">This page</a> says that <code>PropTypes.element</code> is actually a <em>React</em> element, so what's the equivalent for <em>DOM</em> element?</p>