minor #17975 [HttpCache] Add example with an attribute (HypeMC)

This PR was merged into the 6.2 branch.

Discussion
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[HttpCache] Add example with an attribute

Followup to #17972.

Adds an example using an attribute.

Commits
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e992925 [HttpCache] Add example with an attribute

Author: javiereguiluz

http_cache/cache_invalidation.rst

@@ -90,6 +90,22 @@ Then, register the class as a service that :doc:`decorates </service_container/s
 
 .. configuration-block::
 
+    .. code-block:: php-attributes
+
+        // src/CacheKernel.php
+        namespace App;
+
+        // ...
+        use Symfony\Component\DependencyInjection\Attribute\AsDecorator;
+        use Symfony\Component\DependencyInjection\Attribute\Autoconfigure;
+
+        #[Autoconfigure(bind: ['$surrogate' => '@?esi'])]
+        #[AsDecorator(decorates: 'http_cache')]
+        class CacheKernel extends HttpCache
+        {
+            // ...
+        }
+
     .. code-block:: yaml
 
         # config/services.yaml