minor #11556 Fix indention in code example (OskarStark)

This PR was merged into the 4.2 branch.

Discussion
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Fix indention in code example

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Commits
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5c7d9a9 fix indention

Author: wouterj

components/messenger.rst

@@ -272,8 +272,8 @@ do is to write your own CSV receiver::
 
         public function __construct(SerializerInterface $serializer, string $filePath)
         {
-           $this->serializer = $serializer;
-           $this->filePath = $filePath;
+            $this->serializer = $serializer;
+            $this->filePath = $filePath;
         }
 
         public function receive(callable $handler): void