Leaking private type YF from yamlFormatX

[srdo]

Hi.

The yamlFormatX methods in ProductFormats return the YF[A] type. This type is private to moultingyaml, and is an alias for YamlFormat[A]. This causes a problem for tools like Scalafix or IntelliJ.

Say you have a declaration like

implicit val myFormat = yamlFormat1(SomeClass)

If you ask Scalafix or IntelliJ to add a type annotation, it will add YF[SomeClass], which will break the build, as YF is not accessible outside moultingyaml.

I think the easy fix is to make YF accessible to everyone. The slightly nicer fix is probably to drop the type alias from moultingyaml, and just use YamlFormat in the API instead.