minor #16952 Fix doc service deprecation (94noni)

This PR was submitted for the 6.0 branch but it was merged into the 5.4 branch instead.

Discussion
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Fix doc service deprecation

Hi,
Based on [this PR](symfony/symfony#46814), I've followed [the doc](https://symfony.com/doc/current/service_container/alias_private.html#deprecating-services)

But when tests executed, I got [this error](symfony/symfony#46814 (comment))

So I propose to fix the doc accordingly here

Thank you

Commits
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ffdb7e6 Fix documentation on declaration of service deprecation in YAML format

Author: javiereguiluz

service_container/alias_private.rst

@@ -349,7 +349,10 @@ or you decided not to maintain it anymore), you can deprecate its definition:
 
         # config/services.yaml
         App\Service\OldService:
-            deprecated: The "%service_id%" service is deprecated since vendor-name/package-name 2.8 and will be removed in 3.0.
+            deprecated:
+                package: 'vendor-name/package-name'
+                version: '2.8'
+                message: The "%service_id%" service is deprecated since vendor-name/package-name 2.8 and will be removed in 3.0.
 
     .. code-block:: xml