minor symfony#8208 Better aliasing (mercuryseries)

This PR was merged into the 3.3 branch.

Discussion
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Better aliasing

This aliasing will be better in order to be in sync with the previous section.

Commits
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0bf1d12 Better aliasing

Author: xabbuh

service_container/alias_private.rst

@@ -144,7 +144,7 @@ This means that when using the container directly, you can access the
 
         services:
             # ...
-            app.mailer: '@app.phpmailer'
+            app.mailer: '@AppBundle\Mail\PhpMailer'
 
 Deprecating Services
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