Removed mentioning of DummyCache usage

docs/guide/caching-data.md

@@ -68,14 +68,6 @@ For example, you can modify the above configuration to use [[yii\caching\ApcCach
 ],
 ```
 
-Or dummy cache that can be used to remove caching without modifying any code:
-
-```php
-'components' => [
-    'cache' => new yii\caching\DummyCache,
-],
-```
-
 > Tip: You can register multiple cache application components. The component named `cache` is used
   by default by many cache-dependent classes (e.g. [[yii\web\UrlManager]]).