This is about a year's worth of changes, but mostly it just fixes various
typos and cleans up the prose.
I also split off the larger code examples into separate source files, to
make them easier for people to play around with.
There is some new content, but it is incomplete:
- I started writing the 'Existential Types' chapter.
- I started an overhaul of the 'Completion' chapter, including an example of the
"decidable but non-FCRS generic signature", but I still need to think about how
best to structure that proof.
Since the new content is not done or very polished, I'm going to hold off
on updating the PDF that is hosted on swift.org for now. I hope to finish
this stuff off soon, though!