Doc updates and assorted bug fixes
This is a minor update on top of v3.1.0. The only noticeable change at runtime should be that default arguments of scalar String type should be returned properly from Introspection queries.
This is necessary to get GraphiQL working again, now that we include @deprecated(reason: String = "No longer supported")
in the schema. It wanted to parse the string in defaultValue
as a GraphQL input type, and not having the quotes embedded in the response broke the parser.