add ipympl to docs

docs/using/selecting.md

@@ -84,7 +84,7 @@ packages from [conda-forge](https://conda-forge.github.io/feedstocks)
 [numba](https://numba.pydata.org/), [bokeh](https://bokeh.pydata.org/en/latest/), [sqlalchemy](https://www.sqlalchemy.org/), [hdf5](http://www.h5py.org/),
 [vincent](http://vincent.readthedocs.io/en/latest/), [beautifulsoup](https://www.crummy.com/software/BeautifulSoup/),
 [protobuf](https://developers.google.com/protocol-buffers/docs/pythontutorial), and [xlrd](http://www.python-excel.org/) packages
-* [ipywidgets](https://ipywidgets.readthedocs.io/en/stable/) for interactive visualizations in Python notebooks
+* [ipywidgets](https://ipywidgets.readthedocs.io/en/stable/) and [ipympl](https://github.com/matplotlib/jupyter-matplotlib) for interactive visualizations and plots in Python notebooks
 * [Facets](https://github.com/PAIR-code/facets) for visualizing machine learning datasets
 
 ### jupyter/tensorflow-notebook
@@ -206,4 +206,3 @@ binder:[![Binder](https://mybinder.org/badge_logo.svg)](https://mybinder.org/v2/
 
 
 See the [contributing guide](../contributing/stacks.md) for information about how to create your own Jupyter Docker Stack.
-