config.generators javascript_engine default value is :js not nil [ci skip]

guides/source/configuring.md

@@ -187,7 +187,7 @@ The full set of methods that can be used in this block are as follows:
 * `helper` defines whether or not to generate helpers. Defaults to `true`.
 * `integration_tool` defines which integration tool to use. Defaults to `nil`.
 * `javascripts` turns on the hook for JavaScript files in generators. Used in Rails for when the `scaffold` generator is run. Defaults to `true`.
-* `javascript_engine` configures the engine to be used (for eg. coffee) when generating assets. Defaults to `nil`.
+* `javascript_engine` configures the engine to be used (for eg. coffee) when generating assets. Defaults to `:js`.
 * `orm` defines which orm to use. Defaults to `false` and will use Active Record by default.
 * `resource_controller` defines which generator to use for generating a controller when using `rails generate resource`. Defaults to `:controller`.
 * `scaffold_controller` different from `resource_controller`, defines which generator to use for generating a _scaffolded_ controller when using `rails generate scaffold`. Defaults to `:scaffold_controller`.