Documentation error in "Importing Notebooks.html"

**Describe the bug**

This page claims there is a newer version of the notebook, but the link is dead

https://jupyter-notebook.readthedocs.io/en/4.x/examples/Notebook/rstversions/Importing%20Notebooks.html

The link points at this address, which does not exist.

https://jupyter-notebook.readthedocs.io/en/5.7.6/examples/Notebook/rstversions/Importing%20Notebooks.html

Open the cited "Importing Notebooks.html" page and verify the dead link to the 5.7.6 URL, then locate its documentation source in the repository. Done means the page no longer points to a nonexistent address and the documentation link is validated.

Written by the indexing model from the issue text.