Ignore `.ipynb_checkpoints` when building docs (#13929)...
Ignore `.ipynb_checkpoints` when building docs (#13929)
This is a small thing - when editing the docs from JupyterLab Desktop,
any file opened will leave `.ipynb_checkpoints` temp directory. Editing
documentation in Jupyter itself is quite common especially when using
spinx-myst and it is convenient enough for me, but without this change
Sphinx errors out on every other build.