Nested rst:directive:option is un-nested in TOC

[mgeier]

Describe the bug

Follow-up to #10807 (comment).

How to Reproduce

conf.py:

# empty

index.rst:

Hello!
======

.. toctree::

   rst

rst.rst:

reST Domain
===========

This example is taken from
https://www.sphinx-doc.org/en/master/usage/restructuredtext/domains.html#directive-rst-directive-option:

.. rst:directive:: toctree

   .. rst:directive:option:: caption: caption of ToC

   .. rst:directive:option:: glob

Expected behavior

Since rst:directive:option is nested within rst:directive, I would expect it's TOC entry to be nested as well.

Your project

https://insipid-sphinx-theme.readthedocs.io/en/sphinx5.x/showcase/api-doc.html

Screenshots

OS

any

Python version

any

Sphinx version

5.x branch, after #10807

Sphinx extensions

No response

Extra tools

No response

Additional context

No response