feat(typesetters): Discourage page breaks after hyphenated lines

[Omikhleia]

When typesetting a real book, sooner or later, the following occurs:

Most typographers would frown upon hyphenated words at the end of a page (even so more if the page ends being a right page).

Is this a bug? Well yes if SILE reportedly pretends being as good as TeX already.
Otherwise it's a "feature", implementing the missing TeX "brokenpenalty".

So here it is...

Simplified MWE

\begin[papersize=a7]{document}
\neverindent
\nofolios
\font[family=Libertinus Serif, size=12pt]
\language[main=en]

Check page break.

% Ad hoc skip to trigger the issue, with some flexibility to allow for lines to
% move around.
% Some lines of text, our sentence with a long word ("desintructionalizations")
% that we expect to be hyphenated, and some more text.
% The game is for our word to be broken, but not conflict with orphan/widow lines.
\skip[height=6.5cm plus 1cm minus 1cm]

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam nec purus nec nunc ultricies ultricies.
Desintructionalizations may lead to revolutions in the future.

\end{document}

Observed

Expected (fixed)

It should be a good thing to start with.¹

Footnotes

1. To be honest, there's more to be discussed on the topic...
   - Esp. with footnotes, where this could be more "acceptable" (say some) (so what value should be active with footnotes is a question for the footnote logic)
   - And... Er... on the main text content with footnotes again, due to the way they can be split or not, etc. and how the current pagebuilder computes penalties and badness. ↩

[Omikhleia]

NOTE.
This will obviously affect existing books. If needed, one can set typesetter.brokenpenalty to 0 and the output will then be the same as before. I'm not sure we should put that in "retrograde" or not.