minor #13105 [3.4] patch for dependency injection in controllers (DurandSacha)

This PR was submitted for the master branch but it was squashed and merged into the 3.4 branch instead.

Discussion
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[3.4] patch for dependency injection in controllers

Symfony packs a whole class, not objects !

Commits
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41fb362 [3.4] patch for dependency injection in controllers

Author: OskarStark

controller.rst

@@ -254,7 +254,7 @@ Fetching Services as Controller Arguments
     The ability to type-hint a controller argument in order to receive a service
     was introduced in Symfony 3.3.
 
-Symfony comes *packed* with a lot of useful objects, called :doc:`services </service_container>`.
+Symfony comes *packed* with a lot of useful classes and functionalities, called :doc:`services </service_container>`.
 These are used for rendering templates, sending emails, querying the database and
 any other "work" you can think of.