This release contains a semver-breaking change. Zero-sized array types
where the item type does not implement `Settings` itself won't have an
impl for `Settings` anymore. Or to put it in Rust terms,
`[T; 0]: !Settings where T: !Settings`.

We decided to make this change in a minor release because we don't
believe anyone uses zero-sized array types as `Settings` in practice. A
best-effort workaround is in place for `#[derive(Settings)]` on structs
with `[T; 0]` members.

For more details on why this change was made in the first place, see
commit 7b2c1c2be9230c466d8498e915df258934d8300c.