Notice that as an after effect ``Contents`` or ``Python Module Index``
will appear (by default) in bold, and larger than formerly (it was a
bug of Sphinx that they were not styled).
I am leaving the `\py@HeaderFamily` in the `sphinx.sty` patch to the
Bjarne `fncychap.sty` style for backwards compatibility. And as it does
`\bfseries` by default I left only the size changing commands in the
`fncychap` customization of Bjarne style.
Also, the `\@makechapterhead` re-definition obeys `\mainmatter` etc...