Inheritance diagrams are excessively large in 3.2.0 docs

Compare
https://matplotlib.org/3.2.0/api/artist_api.html#matplotlib.artist
vs
https://matplotlib.org/devdocs/api/artist_api.html#matplotlib.artist

We're using svg diagrams now (#16113). But that applies to both 3.2.0 and devdocs. So that alone cannot explain it. Are the versioned docs built differently?
