Right indentation for tip

Author: aferrandini

cookbook/email/gmail.rst

@@ -55,15 +55,15 @@ You're done!
 
     If you are using Symfony Standard Edition, configure the parameters at ``parameters.yml``:
 
-.. code-block:: yaml
-
-    # app/config/parameters.yml
-    parameters:
-        ...
-        mailer_transport: gmail
-        mailer_host:      ~
-        mailer_user:      your_gmail_username
-        mailer_password:  your_gmail_password
+    .. code-block:: yaml
+
+        # app/config/parameters.yml
+        parameters:
+            ...
+            mailer_transport: gmail
+            mailer_host:      ~
+            mailer_user:      your_gmail_username
+            mailer_password:  your_gmail_password
 
 .. note::