The remaining two were core::str::FromStr and
alloc::collections::BTreeMap.
Note that this doesn’t allow us to be no_std yet.
skip-changelog: This isn’t in any way user-visible, except that some
structs are now slightly smaller.
Let’s continue reexporting jid and minidom, but not their inner pub
items, users of this crate can go one level deeper if they need that.
Only xso::error::Error is still useful to reexport, as this is part of
the public API of all of our parsers.
