Increasing the depth of the PDF TOC

[john-science]

What is the change? Why is it being made?

close #2414

SCR Information

Change Type: docs

One-Sentence Rationale: TBD

One-line Impact on Requirements: NA

---

Checklist

• This PR has only one purpose or idea.
• Tests have been added/updated to verify any new/changed code.
• The documentation is still up-to-date in the doc folder.
• The code style follows good practices.
• The dependencies are still up-to-date in pyproject.toml.

[john-science]

No success yet.

[github-actions]

This pull request has been automatically marked as stale because it has not had any activity in the last 100 days. It will be closed in 7 days if no further activity occurs. Thank you for your contributions.