Clarify BackendObjectReference Port field godoc

* apis/v1beta1/object_reference_types.go (BackendObjectReference): Clarify
that the Port field references the service port number when the backend
is a Kubernetes Service.
* config/crd/experimental/gateway.networking.k8s.io_httproutes.yaml:
* config/crd/standard/gateway.networking.k8s.io_httproutes.yaml:
Regenerate.

Author: Miciah

apis/v1beta1/object_reference_types.go

@@ -123,7 +123,8 @@ type BackendObjectReference struct {
 	Namespace *Namespace `json:"namespace,omitempty"`
 
 	// Port specifies the destination port number to use for this resource.
-	// Port is required when the referent is a Kubernetes Service.
+	// Port is required when the referent is a Kubernetes Service.  In this
+	// case, the port number is the service port number, not the target port.
 	// For other resources, destination port might be derived from the referent
 	// resource or this field.
 	//