Add ref to how-to for grpc web

blog/2024-12-11-whats-new-in-vert-x-5.mdx

@@ -75,7 +75,9 @@ The Vert.x gRPC Server supports the [gRPC Web](https://github.com/grpc/grpc/blob
 protocol by default (i.e. without an intermediate proxy).
 
 On the Vert.x side, enabling the gRPC Web protocol support is a mere switch in options.
-In the near feature, we will provide a [tutorial](https://how-to.vertx.io/) explaining how to generate a browser client with `protoc` and to communicate with the server.
+
+This [How-to](https://vertx.io/docs/howtos/grpc-web-howto/) explains how to generate a browser client
+with `protoc` and to communicate with the server.
 
 ### gRPC deadlines