Remove override annotation from snippets to avoid breaking javadoc (#1287)

Author: mziccard

google-cloud-examples/src/main/java/com/google/cloud/examples/pubsub/snippets/PubSubSnippets.java

@@ -557,7 +557,6 @@ public void pullAsync(String subscriptionName) throws ExecutionException, Interr
   public void pullWithMessageConsumer(String subscriptionName) throws Exception {
     // [START pullWithMessageConsumer]
     MessageProcessor callback = new MessageProcessor() {
-      @Override
       public void process(Message message) throws Exception {
         // Ack deadline is renewed until this method returns
         // Message is acked if this method returns successfully

google-cloud-examples/src/main/java/com/google/cloud/examples/pubsub/snippets/SubscriptionSnippets.java

@@ -208,7 +208,6 @@ public void pullAsync() throws ExecutionException, InterruptedException {
   public void pullWithMessageConsumer(String subscriptionName) throws Exception {
     // [START pullWithMessageConsumer]
     MessageProcessor callback = new MessageProcessor() {
-      @Override
       public void process(Message message) throws Exception {
         // Ack deadline is renewed until this method returns
         // Message is acked if this method returns successfully

google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/PubSub.java

@@ -771,7 +771,6 @@ interface MessageConsumer extends AutoCloseable {
    * <pre> {@code
    * String subscriptionName = "my_subscription_name";
    * MessageProcessor callback = new MessageProcessor() {
-   *   @Override
    *   public void process(Message message) throws Exception {
    *     // Ack deadline is renewed until this method returns
    *     // Message is acked if this method returns successfully

google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/Subscription.java

@@ -371,7 +371,6 @@ public Future<Iterator<ReceivedMessage>> pullAsync(int maxMessages) {
    * <pre> {@code
    * String subscriptionName = "my_subscription_name";
    * MessageProcessor callback = new MessageProcessor() {
-   *   @Override
    *   public void process(Message message) throws Exception {
    *     // Ack deadline is renewed until this method returns
    *     // Message is acked if this method returns successfully