Unused definitions produced for simple newtypes

[fizruk]

Generic mechanism sometimes declares unused definitions.
Below is an example of when this happens.

Declare a common type with a named schema:

>>> newtype Id = Id String deriving Generic
>>> instance ToParamSchema Id where toParamSchema _ = toParamSchema (Proxy :: Proxy String) & schemaFormat ?~ "uuid"
>>> instance ToSchema Id where declareNamedSchema = return . paramSchemaToNamedSchema defaultSchemaOptions

Wrap that named typed in a simple newtype:

>>> newtype UserId = UserId Id deriving Generic
>>> instance ToSchema UserId

Generic mechanism does not need to produce definition for Id, but it does so nonetheless.

>>> encode $ runDeclare (declareNamedSchema (Proxy :: Proxy UserId)) mempty
"[{\"Id\":{\"format\":\"uuid\",\"type\":\"string\"}},[\"UserId\",{\"format\":\"uuid\",\"type\":\"string\"}]]"

Fix should be simple enough.