showdownjs/test/functional/makehtml/cases/features/tables/#179.parse-md-in-table-ths.html

<table>
  <thead>
    <tr>
      <th><em>foo</em></th>
      <th><strong>bar</strong></th>
      <th><del>baz</del></th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>100</td>
      <td>blabla</td>
      <td>aaa</td>
    </tr>
  </tbody>
</table>