Make mention of graphql:scalar in the guide
Make mention of graphql:scalar in the guide

nevesenin/graphql-ruby,nevesenin/graphql-ruby,rmosolgo/graphql-ruby,xuorig/graphql-ruby,nevesenin/graphql-ruby,nevesenin/graphql-ruby,rmosolgo/graphql-ruby,xuorig/graphql-ruby,rmosolgo/graphql-ruby,rmosolgo/graphql-ruby,xuorig/graphql-ruby