Add section on code generation to the documentation #847
Description
This has been discussed previously in #472 and #159, but nothing in our documentation yet.
We don't support generation of classes, but it's possible to use the DGS codegen plugin, which is especially useful for access to remote GraphQL services by using generated types to prepare the request (e.g. query, mutation, and projections). This is easy to use with our GraphQlClient and GraphQlTester.
It would be good to document that for a start. We'll also explore making it simpler in #846 and also spring-io/start.spring.io#1348.