docs: Update intersphinx_mapping

docs: Update intersphinx_mapping

Running `make dirhtml` in bindings/python/docs generates the following
error:

```
sphinx-build -b dirhtml -d build/doctrees   source build/dirhtml
Running Sphinx v8.0.2
loading translations [en]... done
making output directory... done
Converting `source_suffix = '.rst'` to `source_suffix = {'.rst': 'restructuredtext'}`.
ERROR: Invalid value `None` in intersphinx_mapping['https://docs.python.org/']. Expected a two-element tuple or list.
```

This commit updates intersphinx_mapping to follow the latest docs [1]

[1] https://www.sphinx-doc.org/en/master/usage/extensions/intersphinx.html

Signed-off-by: Fredrik Lönnegren <fredrik@frelon.se>