remove whitespace to make sure link is absolute

Author: DanielSchwiperich

core/getting-started.md

@@ -213,7 +213,7 @@ The API Platform's configuration (annotations, `YAML` or `XML`) only allow to co
 * The `denormalization_context` key will be passed as 4th argument of [the `Serializer::deserialize()` method](https://api.symfony.com/master/Symfony/Component/Serializer/SerializerInterface.html#method_deserialize)
 
 
-To configure the serialization groups of classes's properties, you must use directly [the Symfony Serializer's configuration files or annotations]( https://symfony.com/doc/current/components/serializer.html#attributes-groups).
+To configure the serialization groups of classes's properties, you must use directly [the Symfony Serializer's configuration files or annotations](https://symfony.com/doc/current/components/serializer.html#attributes-groups).
 
 **You're done!**