Record extension fails roc check

[jacob-2]

This:

Foo : { foo : Str }
Bar : { bar : Str }Foo

gives roc check error:

── INVALID_EXTENSION_TYPE in test2.roc ─────────────────────────────────────────

This record extension type is invalid:

20│  Bar : { bar : Str }Foo
                        ^^^

Note: A record extension variable can only contain a type variable or
another record.

Expected record extension like Bar : { foo : Str, bar : Str }