minor #11438 Documented the LoggerAwareInterface autoconfiguration (javiereguiluz)

This PR was squashed before being merged into the 4.2 branch (closes #11438).

Discussion
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Documented the LoggerAwareInterface autoconfiguration

Fixes #10188.

Commits
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7305bf0 Documented the LoggerAwareInterface autoconfiguration

Author: javiereguiluz

logging.rst

@@ -338,6 +338,16 @@ option of your handler to ``rotating_file``:
 Using a Logger inside a Service
 -------------------------------
 
+If your application uses :ref:`service autoconfiguration <services-autoconfigure>`,
+any service whose class implements ``Psr\Log\LoggerAwareInterface`` will
+receive a call to its method ``setLogger()`` with the default logger service
+passed as a service.
+
+.. versionadded:: 4.2
+
+    The automatic call to ``setLogger()`` when implementing ``LoggerAwareInterface``
+    was introduced in Symfony 4.2.
+
 If you want to use in your own services a pre-configured logger which uses a
 specific channel (``app`` by default), use the ``monolog.logger`` tag  with the
 ``channel`` property as explained in the