Deprecate enum, enumA, wrappedEnum, wrappedEnumA

These functions are from Language.GraphQL.Schema.
There are actually only two generic types in GraphQL: Scalars and objects.
Enum is a scalar value. According to the specification enums may be
serailized to strings. And in the current implementation they used
untyped strings anyway, so there is no point to have differently named
functions with the same implementation as their scalar counterparts.

src/Language/GraphQL/Schema.hs

@@ -111,18 +111,17 @@ wrappedScalar :: (MonadIO m, Aeson.ToJSON a)
     => Name -> ActionT m (Wrapping a) -> Resolver m
 wrappedScalar name = wrappedScalarA name . const
 
--- | Represents one of a finite set of possible values.
---   Used in place of a 'scalar' when the possible responses are easily enumerable.
+{-# DEPRECATED enum "Use scalar instead" #-}
 enum :: MonadIO m => Name -> ActionT m [Text] -> Resolver m
 enum name = enumA name . const
 
--- | Like 'enum' but also taking 'Argument's.
+{-# DEPRECATED enumA "Use scalarA instead" #-}
 enumA :: MonadIO m => Name -> (Arguments -> ActionT m [Text]) -> Resolver m
 enumA name f = Resolver name $ resolveFieldValue f resolveRight
   where
     resolveRight fld resolver = withField (return resolver) fld
 
--- | Like 'enum' but also taking 'Argument's and can be null or a list of enums.
+{-# DEPRECATED wrappedEnumA "Use wrappedScalarA instead" #-}
 wrappedEnumA :: MonadIO m
     => Name -> (Arguments -> ActionT m (Wrapping [Text])) -> Resolver m
 wrappedEnumA name f = Resolver name $ resolveFieldValue f resolveRight
@@ -132,7 +131,7 @@ wrappedEnumA name f = Resolver name $ resolveFieldValue f resolveRight
         = return $ HashMap.singleton (aliasOrName fld) Aeson.Null
     resolveRight fld (List resolver) = withField (return resolver) fld
 
--- | Like 'enum' but can be null or a list of enums.
+{-# DEPRECATED wrappedEnum "Use wrappedScalar instead" #-}
 wrappedEnum :: MonadIO m => Name -> ActionT m (Wrapping [Text]) -> Resolver m
 wrappedEnum name = wrappedEnumA name . const