docs: mention other execution libs in the index (#264)

Author: 12rambau

docs/index.rst

@@ -11,11 +11,7 @@ Jupyter Sphinx Extension
    options
    changelog <https://github.com/jupyter/jupyter-sphinx/releases>
 
-Jupyter-sphinx is a Sphinx extension that executes embedded code in a Jupyter
-kernel, and embeds outputs of that code in the document. It has support
-for rich output such as images, Latex math and even javascript widgets, and
-it allows to enable `thebelab <https://thebelab.readthedocs.io/>`_ for live
-code execution with minimal effort.
+Jupyter-sphinx is a Sphinx extension that executes embedded code in a Jupyter kernel, and embeds outputs of that code in the document. It has support for rich output such as images, Latex math and even javascript widgets, and it allows to enable `thebelab <https://thebelab.readthedocs.io/>`_ for live code execution with minimal effort.
 
 .. code-block:: rst
 
@@ -44,3 +40,7 @@ code execution with minimal effort.
         :link: thebelab.html
 
         Discover how ``ThebeLab`` is linked to ``jupyter-sphinx``.
+
+.. seealso::
+
+    Other extensions exist to display output of IPyhton cells in a Sphinx documentation. If you want to execute entire notebooks you can consider using `nbsphinx <https://nbsphinx.readthedocs.io>`__ or `myst-nb <https://myst-nb.readthedocs.io/>`__. For in-page live execution consider using `sphinx-thebe <https://sphinx-thebe.readthedocs.io/>`__ or `jupyterlite-sphinx <https://jupyterlite-sphinx.readthedocs.io/>`__. For users that don't need to rely on a jupyter kernel the lightweigth `IPython sphinx directive <https://ipython.readthedocs.io/en/stable/sphinxext.html#ipython-sphinx-directive>`__ can be used but remember it will only be able to display text outputs.