fix: Fix typo in generated comment (#1006)

Author: vam-google

src/main/java/com/google/api/generator/gapic/composer/comment/ServiceClientCommentComposer.java

@@ -56,7 +56,7 @@ public class ServiceClientCommentComposer {
   private static final String SERVICE_DESCRIPTION_ENDPOINT_SUMMARY_STRING =
       "To customize the endpoint:";
   private static final String SERVICE_DESCRIPTION_TRANSPORT_SUMMARY_STRING =
-      "To use %s transport (instead of %s) for sending an receiving requests over the wire:";
+      "To use %s transport (instead of %s) for sending and receiving requests over the wire:";
 
   private static final String SERVICE_DESCRIPTION_SAMPLE_REFERENCE_STRING =
       "Please refer to the GitHub repository's samples for more quickstart code snippets.";

src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/EchoClient.golden

@@ -87,7 +87,7 @@ import javax.annotation.Generated;
  * EchoClient echoClient = EchoClient.create(echoSettings);
  * }</pre>
  *
- * <p>To use REST (HTTP1.1/JSON) transport (instead of gRPC) for sending an receiving requests over
+ * <p>To use REST (HTTP1.1/JSON) transport (instead of gRPC) for sending and receiving requests over
  * the wire:
  *
  * <pre>{@code

src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/EchoEmpty.golden

@@ -67,7 +67,7 @@ import javax.annotation.Generated;
  * EchoEmpyClient echoEmpyClient = EchoEmpyClient.create(echoEmpySettings);
  * }</pre>
  *
- * <p>To use REST (HTTP1.1/JSON) transport (instead of gRPC) for sending an receiving requests over
+ * <p>To use REST (HTTP1.1/JSON) transport (instead of gRPC) for sending and receiving requests over
  * the wire:
  *
  * <pre>{@code