showdownjs/test/functional/makehtml/cases/issues/#495.headings-different-behavior-in-paragraphs-and-lists.html

<ul>
  <li>Increase the number of water changes.</li>
  <li><h1 id="proteinskimmers">Protein skimmers:</h1>
    <p>This remove dissolved</p></li>
  <li><h1 id="chemicalfiltermedia">Chemical filter media:</h1>
    <p>When placed in your filter</p></li>
<li>#</li>
<li>something</li>
<li>#
  something</li>
<li># something</li>
</ul>