Make cretonne-codegen's `result` module private, and instead just export `CodegenError` and `CodegenResult` at the top level of the cretonne-codegen crate. This makes them more consistent with Result and Error types in other cretonne crates.
Make cretonne-codegen's `result` module private, and instead just export `CodegenError` and `CodegenResult` at the top level of the cretonne-codegen crate. This makes them more consistent with Result and Error types in other cretonne crates.