Custom scalars and UnmarshalJSON: UnmarshalGQL ignored

[geertjanvdk]

Reading the docs about Scalars, one can see that you can implement graphql.Marshaler with the method UnmarshalGQL to decode.

However, it would be great to mention that UnmarshalJSON takes precedence, and UnmarshalGQL gets ignored. Granted, probably both have to do the same thing (unless crazy stuff like using XML instead of JSON for GraphQL, which is technically possible).

Wanted to open a discussion first, maybe I missed a note somewhere. Took me a while to figure out what was happening. Now both methods are implemented, and execute the same decoding.