COMP: Enable IPython.sphinxext.ipython_console_highlighting

To address:

```
ConvertNumPyArrayToitkImage.ipynb:: WARNING: Pygments lexer name 'ipython3' is not known
```

per:

- spatialaudio/nbsphinx#24

Also install ipywidgets for general use in the Superbuild.

Author: thewtex

Formatting/conf.py.in

@@ -40,7 +40,9 @@ primary_domain = 'cpp'
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
 extensions = ['sphinx.ext.todo', 'sphinx.ext.imgmath', 'sphinx.ext.ifconfig',
-    'sphinx.ext.viewcode', 'sphinx.ext.imgconverter', 'breathe', 'doxylink', 'breathelink', 'nbsphinx', 'sphinx_contributors']
+    'sphinx.ext.viewcode', 'sphinx.ext.imgconverter', 'breathe', 'doxylink',
+    'breathelink', 'nbsphinx', 'sphinx_contributors',
+    'IPython.sphinxext.ipython_console_highlighting',]
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['templates']

Superbuild/External-Python.cmake

@@ -17,6 +17,6 @@ ExternalProject_Add(ITKPython
   DOWNLOAD_COMMAND ""
   CONFIGURE_COMMAND ${PYTHON_EXECUTABLE} -m venv "${_itk_venv}"
   BUILD_COMMAND ${ITKPYTHON_EXECUTABLE} -m pip install --upgrade pip
-  INSTALL_COMMAND ${ITKPYTHON_EXECUTABLE} -m pip install --ignore-installed itk>=5.3.0 sphinx==4.4.0 docutils<0.18 six black nbsphinx ipython sphinx-contributors ipykernel matplotlib itkwidgets[lab,notebook]>=1.0a21 pydata-sphinx-theme
+  INSTALL_COMMAND ${ITKPYTHON_EXECUTABLE} -m pip install --ignore-installed itk>=5.3.0 sphinx==4.4.0 docutils<0.18 six black nbsphinx ipywidgets sphinx-contributors ipykernel matplotlib itkwidgets[lab,notebook]>=1.0a21 pydata-sphinx-theme
   COMMAND ${CMAKE_COMMAND} -P ${CMAKE_CURRENT_BINARY_DIR}/ITKBlackConfig.cmake
   )