Evaluate Utility of sphinx-prompt

[michaelweinold]

...perhaps following up on the conversation here:

• Refactor theory to overview #165 (comment)

After all, it is not clear if this extension is still needed:

• Is this extension still relevant with Sphinx 4.1? sbrunner/sphinx-prompt#107

[michaelweinold]

We actually don't need sphinx-prompt. Sphinx itself recognizes prompt characters >>> and I have now configured sphinx-copybutton to do the same.

These code cells:

when copied will now yield:

from pandas import DataFrame
df = sp.statistics()

sp.statistics()

@cmutel, please just use >>> instead of >.