joplin/packages/app-cli/tests/md_to_html/toc_duplicate_items.html

<nav class="table-of-contents"><ul><li><a href="#test">test</a></li><li><a href="#test-2">test</a></li><li><a href="#test2">test2</a></li></ul></nav><h1 id="test">test</h1>
<h1 id="test-2">test</h1>
<h1 id="test2">test2</h1>