This PR adds support for **HTML** both ordered and unordered lists.

<img width="1441" height="805" alt="Screenshot 2025-10-07 at 21 40 17"
src="https://github.com/user-attachments/assets/8a54aec1-75aa-48fb-bf9f-c153cca48682"
/>

See code example used inside the screenshot:

```html
<ol>
  <li>First item</li>
  <li>Second item</li>
  <li>Third item
    <ol>
      <li>Indented item</li>
      <li>Indented item</li>
    </ol>
  </li>
  <li>Fourth item</li>
</ol>
```

TODO: 
- [x] Add examples
- [x] update description (screenshots, add small description)
- [x] fix displaying of nested lists

cc @bennetbo

Release Notes:

- markdown preview: Added support for HTML lists

---------

Co-authored-by: Bennet Bo Fenner <bennetbo@gmx.de>