Add region tags around an informative sample. (#3705)

Author: frankyn

google-cloud-examples/src/main/java/com/google/cloud/examples/storage/snippets/CreateBlob.java

@@ -36,9 +36,11 @@
 public class CreateBlob {
 
   public static void main(String... args) {
+    // [START storage_upload_file]
     Storage storage = StorageOptions.getDefaultInstance().getService();
     BlobId blobId = BlobId.of("bucket", "blob_name");
     BlobInfo blobInfo = BlobInfo.newBuilder(blobId).setContentType("text/plain").build();
     Blob blob = storage.create(blobInfo, "Hello, Cloud Storage!".getBytes(UTF_8));
+    // [END storage_upload_file]
   }
 }