inline docs mechanisms for playground

[quinn-dougherty]

There's plenty of screen real-estate to play with this

Inspiration

• jupyter's ? prefix to a callable exposes the docs. so ?stats.normal prints the appropriate docstring.
• Streamlit's st.write command, for printing, doubles as jupyter's ? operator functionality. (try st.write(st.header) in this)

Regarding hoverover

Not clear to me if hover-over should display docs of the functions being called or display distributions (or values) at intermediary computations.