Documentation: how to configure GrafViz?

[datamusee]

I'm really impressed by your very useful tool and I've produced several notebooks at the moment, like:
https://github.com/datamusee/notebooks/blob/main/Les%20mouvements%20artistiques%20de%20la%20base%20Joconde%20sur%20Wikidata.ipynb

I would like to set GrafViz as a known extension for sparql-kernel, but I doesn't understand how to do it.
I will use ubuntu next, but now, i'm using windows 10.
GrafViz is installed on my computer and in the PATH. But all my trials with the magic
%display diagram svg
gives the same things that
%display table