Write a function that takes in a [KDL schema spec](https://github.com/kdl-org/kdl/blob/main/SCHEMA-SPEC.md) and returns a `Decoder` that can be used to parse KDL files with that schema
Write a function that takes in a KDL schema spec and returns a
Decoderthat can be used to parse KDL files with that schema