fix: modernize the docs regarding custom filters

core/filters.md

@@ -905,74 +905,110 @@ final class RegexpFilter extends AbstractContextAwareFilter
 }
 ```
 
-Then, register this filter as a service:
+Thanks to [Symfony's automatic service loading](https://symfony.com/doc/current/service_container.html#service-container-services-load-example), which is enabled by default in the API Platform distribution, the filter is automatically registered as a service!
 
-```yaml
-# api/config/services.yaml
-services:
-    # ...
-    'App\Filter\RegexpFilter':
-        # Uncomment only if autoconfiguration isn't enabled
-        #tags: [ 'api_platform.filter' ]
-```
+Finally, add this filter to resources you want to be filtered by using the `ApiFilter` annotation:
 
-In the previous example, the filter can be applied on any property. However, thanks to the `AbstractFilter` class,
-it can also be enabled for some properties:
+```php
+<?php
+// api/src/Entity/Offer.php
 
-```yaml
-# api/config/services.yaml
-services:
-    'App\Filter\RegexpFilter':
-        arguments: [ '@doctrine', ~, '@?logger', { email: ~, anOtherProperty: ~ } ]
-        # Uncomment only if autoconfiguration isn't enabled
-        #tags: [ 'api_platform.filter' ]
+namespace App\Entity;
+
+use ApiPlatform\Core\Annotation\ApiFilter;
+use ApiPlatform\Core\Annotation\ApiResource;
+use App\Filter\RegexpFilter;
+
+/**
+ * @ApiResource
+ * @ApiFilter(RegexpFilter::class)
+ */
+class Offer
+{
+    // ...
+}
 ```
 
-Finally, add this filter to resources you want to be filtered:
+You can now use this filter in the URL like `http://example.com/offers?regexp_email=^[FOO]`. This new filter will also
+appear in OpenAPI and Hydra documentations.
+
+In the previous example, the filter can be applied on any property. You can also apply this filter on a specific property:
 
 ```php
 <?php
 // api/src/Entity/Offer.php
 
 namespace App\Entity;
 
+use ApiPlatform\Core\Annotation\ApiFilter;
 use ApiPlatform\Core\Annotation\ApiResource;
 use App\Filter\RegexpFilter;
 
 /**
- * @ApiResource(attributes={"filters"={RegexpFilter::class}})
+ * @ApiResource
  */
 class Offer
 {
     // ...
+
+    /**
+     * @ApiFilter(RegexpFilter::class)
+     */
+    public string $name;
 }
 ```
 
-Or by using the `ApiFilter` annotation:
+#### Manual Service and Attribute Registration
+
+If you don't use Symfony's automatic service loading, you have to register the filter as a service by yourself.
+Use the following service definition (remember, by default, this isn't needed!):
+
+```yaml
+# api/config/services.yaml
+services:
+    # ...
+    # This whole definition can be omitted if automatic service loading is enabled
+    'App\Filter\RegexpFilter':
+        # The "arguments" key can be omitted if the autowiring is enabled
+        arguments: [ '@doctrine', ~, '@?logger' ]
+        # The "tags" key can be omitted if the autoconfiguration is enabled
+        tags: [ 'api_platform.filter' ]
+```
+
+In the previous example, the filter can be applied on any property. However, thanks to the `AbstractFilter` class,
+it can also be enabled for some properties:
+
+```yaml
+# api/config/services.yaml
+services:
+    'App\Filter\RegexpFilter':
+        arguments: [ '@doctrine', ~, '@?logger', { email: ~, anOtherProperty: ~ } ]
+        tags: [ 'api_platform.filter' ]
+```
+
+Finally, if you don't want to use the `@ApiFilter` annotation, you can register the filter on an API resource class using the `filters` attribute:
 
 ```php
 <?php
 // api/src/Entity/Offer.php
 
 namespace App\Entity;
 
-use ApiPlatform\Core\Annotation\ApiFilter;
 use ApiPlatform\Core\Annotation\ApiResource;
 use App\Filter\RegexpFilter;
 
 /**
- * @ApiResource
- * @ApiFilter(RegexpFilter::class)
+ * @ApiResource(
+ *   attributes={
+ *     "filters"={RegexpFilter::class}
+ *   }
+ * )
  */
 class Offer
 {
     // ...
 }
 ```
-When using `ApiFilter` annotation, the declared properties in the `services.yaml` will not be taken into account. You have to use the `ApiFilter` way (see the [documentation](#apifilter-annotation)).
-
-Finally you can use this filter in the URL like `http://example.com/offers?regexp_email=^[FOO]`. This new filter will also
-appear in Swagger and Hydra documentations.
 
 ### Creating Custom Doctrine MongoDB ODM Filters