Merge pull request #5798 from y-zeng/documentation

Doc Fixit: examples/cpp/helloworld/README.md
diff --git a/examples/cpp/helloworld/README.md b/examples/cpp/helloworld/README.md
index 8e11f7c..04283ea 100644
--- a/examples/cpp/helloworld/README.md
+++ b/examples/cpp/helloworld/README.md
@@ -207,7 +207,7 @@
     helloworld::Greeter::AsyncService service;
     ServerBuilder builder;
     builder.AddListeningPort("0.0.0.0:50051", InsecureServerCredentials());
-    builder.RegisterAsyncService(&service);
+    builder.RegisterService(&service);
     auto cq = builder.AddCompletionQueue();
     auto server = builder.BuildAndStart();
     ```