add sh tag

Author: 廖小俊

bigquery/api/README.md

@@ -13,16 +13,16 @@ This simple command-line application demonstrates how to invoke Google BigQuery
     to the path of the JSON key that was downloaded.
 3.  **Clone the repo** and cd into this directory
 
-    ```
-    $ git clone https://github.com/GoogleCloudPlatform/php-docs-samples
+    ```sh
+    $ git clone https://github.com/GoogleCloudPlatform/php-docs-samples
     $ cd php-docs-samples/bigquery/api
     ```
 4.  **Install dependencies** via [Composer](http://getcomposer.org/doc/00-intro.md).
     Run `php composer.phar install` (if composer is installed locally) or `composer install`
     (if composer is installed globally).
 5.  Run `php bigquery.php`. The following commands are available:
 
-    ```
+    ```sh
     browse-table  Browse a BigQuery table
     datasets      List BigQuery datasets
     export        Export data from a BigQuery table into a Cloud Storage bucket