This renames the "sections" list to "items". In practice, this list has
contained more than just "sections" since parts were added. Also, the
rest of the code consistently uses the term "items", since the values it
contains are called `BookItem`s. Finally, the naming has always been a
little confusing to me.
This is a very disruptive change, and I'm not doing it lightly. However,
since there are a number of other API changes going into 0.5, I think
now is an ok time to change this.
This switches all public types to use non_exhaustive to make it easier
to make additions without a semver-breaking change.
Some of the ergonomics are hampered due to the lack of exhaustiveness
checking. Hopefully some day in the future,
non_exhaustive_omitted_patterns_lint or something like it will get
stabilized.
Closes https://github.com/rust-lang/mdBook/issues/1835
This removes the `pub` status of the SectionNumber field. The intent is
to make this potentially extensible in the future if we decide to add
more fields, or change its internal representation. With the existence
of the deref impls, generally this change shouldn't be visible except
for the constructor, which hopefully shouldn't be too cumbersome to use
`SectionNumber::new` instead.
