Update delete-product.js

Author: rebeccaellis

retail/interactive-tutorials/product/delete-product.js

@@ -11,7 +11,7 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
-
+// [START retail_delete_product]
 'use strict';
 
 async function main(generatedProductId) {
@@ -53,3 +53,4 @@ process.on('unhandledRejection', err => {
 });
 
 main(...process.argv.slice(2));
+// [END retail_delete_product]