Interactive plotting broken

In the current version of matplotlib (3.5.2) /ipython (8.4.0) the interactive plotting behaviour has changed. This means that once created, plots do not update (as they are seen to do in the [gif](https://github.com/williamjameshandley/vimteractive/blob/master/images/example_usage.gif)) One fix for this is to run explicitly ```python import matplotlib.pyplot as plt plt.ion() ``` but ideally this would be done with an appropriate set of commands supplied to the `ipython --matplotlib` interpreter so that it works out of the box.