response context support for interceptors

[michelepra]

This is PR for #3863

I think almost anything mentioned in #3864 is implemented

I have:

• Added tests covering the bug / feature (see testing)
• Updated any relevant documentation (see docs)

Feature is exposed under parameter subscription_context_field that is false by default

[StevenACoffman]

@michelepra

After running go generate ./... it linting fails with:

Error: codegen/testserver/subscriptioncontextfield/resolver.go:52:1: File is not properly formatted (gofumpt)
  type mutationResolver struct{ *Resolver }
  ^
  Error: codegen/testserver/subscriptioncontextfield/resolver.go:39:1: File is not properly formatted (golines)
  func (r *subscriptionResolver) UserCreated(ctx context.Context) (<-chan graphql.SubscriptionField[*User], error) {

Then after running golangci-lint run --fix, git diff shows:

diff --git a/codegen/testserver/subscriptioncontextfield/resolver.go b/codegen/testserver/subscriptioncontextfield/resolver.go
index b0dab94a..0d44f4a4 100644
--- a/codegen/testserver/subscriptioncontextfield/resolver.go
+++ b/codegen/testserver/subscriptioncontextfield/resolver.go
@@ -36,7 +36,9 @@ func (r *queryResolver) GetEntity(ctx context.Context, id string) (Entity, error
 }
 
 // UserCreated is the resolver for the userCreated field.
-func (r *subscriptionResolver) UserCreated(ctx context.Context) (<-chan graphql.SubscriptionField[*User], error) {
+func (r *subscriptionResolver) UserCreated(
+	ctx context.Context,
+) (<-chan graphql.SubscriptionField[*User], error) {
 	panic("not implemented")
 }
 
@@ -49,6 +51,8 @@ func (r *Resolver) Query() QueryResolver { return &queryResolver{r} }
 // Subscription returns SubscriptionResolver implementation.
 func (r *Resolver) Subscription() SubscriptionResolver { return &subscriptionResolver{r} }
 
-type mutationResolver struct{ *Resolver }
-type queryResolver struct{ *Resolver }
-type subscriptionResolver struct{ *Resolver }
+type (
+	mutationResolver     struct{ *Resolver }
+	queryResolver        struct{ *Resolver }
+	subscriptionResolver struct{ *Resolver }
+)

So you have changed the templates in a way that does not pass proper Go formatting.