Python 3.12 No module named 'pkg_resources'

Python 3.12.4 on Mac
```
➜ pip install nbdev

➜ nbdev_new
Traceback (most recent call last):
File "/Users/user/Documents/Code/Shell/NBDev_Tutorial/venv/bin/nbdev_new", line 5, in
from nbdev.cli import nbdev_new
File "/Users/user/Documents/Code/Shell/NBDev_Tutorial/venv/lib/python3.12/site-packages/nbdev/__init__.py", line 3, in
from .doclinks import nbdev_export
File "/Users/user/Documents/Code/Shell/NBDev_Tutorial/venv/lib/python3.12/site-packages/nbdev/doclinks.py", line 17, in
import pkg_resources,importlib
ModuleNotFoundError: No module named 'pkg_resources'
```

Fix required mentioned in #1392 and in issue #1397 raised a fix that was closed?

Non-starter trying to follow the tutorial.

Start with nbdev/doclinks.py and reproduce the nbdev_new command under Python 3.12, then review the fixes referenced in issues #1392 and #1397. Done means the command no longer fails with ModuleNotFoundError for pkg_resources and the tutorial can proceed.

Written by the indexing model from the issue text.