Polish "Update broken code examples in docs"

This continues the effort of the previous commit to update
broken code examples.

Author: onobc

README.md

@@ -240,7 +240,7 @@ To create a simple gRPC client, you can use the Spring Boot starter (see above -
 ```java
 @Bean
 SimpleGrpc.SimpleBlockingStub stub(GrpcChannelFactory channels) {
-	return SimpleGrpc.newBlockingStub(channels.createChannel("0.0.0.0:9090").build());
+	return SimpleGrpc.newBlockingStub(channels.createChannel("0.0.0.0:9090"));
 }
 ```
 
@@ -251,7 +251,7 @@ The default `GrpcChannelFactory` implementation can also create a "named" channe
 ```java
 @Bean
 SimpleGrpc.SimpleBlockingStub stub(GrpcChannelFactory channels) {
-	return SimpleGrpc.newBlockingStub(channels.createChannel("local").build());
+	return SimpleGrpc.newBlockingStub(channels.createChannel("local"));
 }
 ```
 

spring-grpc-docs/src/main/antora/modules/ROOT/pages/getting-started.adoc

@@ -250,7 +250,7 @@ To create a simple gRPC client, you can use the Spring Boot starter (see above -
 ----
 @Bean
 SimpleGrpc.SimpleBlockingStub stub(GrpcChannelFactory channels) {
-	return SimpleGrpc.newBlockingStub(channels.createChannel("0.0.0.0:9090").build());
+	return SimpleGrpc.newBlockingStub(channels.createChannel("0.0.0.0:9090"));
 }
 ----
 
@@ -262,7 +262,7 @@ The default `GrpcChannelFactory` implementation can also create a "named" channe
 ----
 @Bean
 SimpleGrpc.SimpleBlockingStub stub(GrpcChannelFactory channels) {
-	return SimpleGrpc.newBlockingStub(channels.createChannel("local").build());
+	return SimpleGrpc.newBlockingStub(channels.createChannel("local"));
 }
 ----