minor #13878 Update upload_file.rst (atailouloute)

This PR was merged into the 4.4 branch.

Discussion
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Update upload_file.rst

Commits
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39541b2 Update upload_file.rst

Author: javiereguiluz

controller/upload_file.rst

@@ -311,7 +311,7 @@ Then, define a service for this class:
                 https://symfony.com/schema/dic/services/services-1.0.xsd">
             <!-- ... -->
 
-            <service id="App\FileUploader">
+            <service id="App\Service\FileUploader">
                 <argument>%brochures_directory%</argument>
             </service>
         </container>