Fix reference and release note nesting (#612)

Compare this [PR
preview](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/612/reference/)
to the [structure used in
AsciiDocalypse](https://docs-v3-preview.elastic.dev/elastic/asciidocalypse/tree/main/docs-content/docs/reference/overview/).

| Before | After |
|---|---|
| <img width="275" alt="Screenshot 2025-02-26 at 6 47 08 PM"
src="https://github.com/user-attachments/assets/d80084b9-f7c3-44b2-9e1e-0b8c8fa3027e"
/> | <img width="347" alt="image"
src="https://github.com/user-attachments/assets/b854e445-9a66-4ccc-87c2-28797759386a"
/> |

Author: colleenmcginnis