Disclosure widget in text

### Describe feature

Add a disclosure widget (expandable section) when writing text, similar to the one natively available in HTML. For example:
<details>
  <summary>Show more</summary>
  <p>This is the text that appears when you expand the section.</p>
</details>

### Additional Information

This feature already exists in Google Docs where you can hide text under a heading with a toggle.