explicitly state TLS termination location (#10516)

docs/examples/grpc/README.md

@@ -9,6 +9,7 @@ This example demonstrates how to route traffic to a gRPC service through the Ing
 3. You have the ingress-nginx-controller installed as per docs.
 4. You have a backend application running a gRPC server listening for TCP traffic.  If you want, you can use <https://github.com/grpc/grpc-go/blob/91e0aeb192456225adf27966d04ada4cf8599915/examples/features/reflection/server/main.go> as an example.
 5. You're also responsible for provisioning an SSL certificate for the ingress. So you need to have a valid SSL certificate, deployed as a Kubernetes secret of type `tls`, in the same namespace as the gRPC application.
+   - Note: To use gRPC with ingress-nginx, TLS _must_ be terminated by the ingress or gRPC server (using the `backend-protocol: "GRPCS"` annotation described below). 
 
 ### Step 1: Create a Kubernetes `Deployment` for gRPC app