python-jupyter-sphinx fails to build with Sphinx 7.2.6 on Fedora Rawhide (40+).

The issue detected:
```
+ /usr/bin/pytest
============================= test session starts ==============================
platform linux -- Python 3.12.0, pytest-7.4.2, pluggy-1.3.0
rootdir: /builddir/build/BUILD/jupyter-sphinx-0.4.0
plugins: anyio-3.7.1
collected 0 items / 1 error

==================================== ERRORS ====================================
____________________ ERROR collecting tests/test_execute.py ____________________
ImportError while importing test module '/builddir/build/BUILD/jupyter-sphinx-0.4.0/tests/test_execute.py'.
Hint: make sure your test modules/packages have valid Python names.
Traceback:
/usr/lib64/python3.12/importlib/__init__.py:90: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
tests/test_execute.py:15: in <module>
    from sphinx.testing.util import SphinxTestApp, assert_node, path
E   ImportError: cannot import name 'path' from 'sphinx.testing.util' (/usr/lib/python3.12/site-packages/sphinx/testing/util.py)
=========================== short test summary info ============================
ERROR tests/test_execute.py
!!!!!!!!!!!!!!!!!!!! Interrupted: 1 error during collection !!!!!!!!!!!!!!!!!!!!
=============================== 1 error in 0.39s ===============================
```

From the Sphinx' changelog:
#11526: Deprecate sphinx.testing.path. Use os.path or pathlib instead.


For the logs from testing build attempts, see:
https://copr.fedorainfracloud.org/coprs/ksurma/sphinx-7.2.6/package/python-jupyter-sphinx

You can test you package in mock running:

$ mock -r fedora-rawhide-x86_64 --addrepo=https://download.copr.fedorainfracloud.org/results/ksurma/sphinx-7.2.6/fedora-rawhide-x86_64/ --no-clean your.src.rpm
$ mock -r fedora-rawhide-x86_64 --addrepo=https://download.copr.fedorainfracloud.org/results/ksurma/sphinx-7.2.6/fedora-rawhide-x86_64/ shell

We'd like to include Sphinx 7.2.x in Fedora 40.

Let us know here if you have any questions. Thank You!