Update index.rst

Author: Bevan

doc/index.rst

@@ -285,15 +285,14 @@ the following parameters to avoid the validation error triggered by Guzzle :
 
     .. code-block:: yaml
 
-      default:
-        extensions:
-          Behat\MinkExtension\Extension:
-            zombie:
-              # Specify the path to the node_modules directory.
-              node_modules_path: /usr/local/lib/node_modules/
-            default_session: 'zombie'
-            javascript_session: 'zombie'
-                              
+        default:
+            extensions:
+                Behat\MinkExtension:
+                    sessions:
+                        default:
+                            zombie:
+                                # Specify the path to the node_modules directory.
+                                node_modules_path: /usr/local/lib/node_modules/
 
 .. note::