docs(introduction): add export statement for config in config.js example

Author: KristjanESPERANTO

configuration/introduction.md

@@ -19,6 +19,9 @@
        },
      ],
    };
+
+   /*************** DO NOT EDIT THE LINE BELOW ***************/
+   if (typeof module !== "undefined") {module.exports = config;}
    ```
 
    See [module configuration](/modules/configuration) for more information and