minor symfony#11884 fix using the doc role for internal reference (xabbuh)

This PR was merged into the 4.2 branch.

Discussion
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fix using the doc role for internal reference

fixes symfony#11880

Commits
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6053234 fix using the doc role for internal reference

Author: javiereguiluz

service_container/compiler_passes.rst

@@ -68,7 +68,7 @@ and process the services inside the ``process()`` method::
 Working with Compiler Passes in Bundles
 ---------------------------------------
 
-`Bundles </bundles>`_ can define compiler passes in the ``build()`` method of
+:doc:`Bundles </bundles>` can define compiler passes in the ``build()`` method of
 the main bundle class (this is not needed when implementing the ``process()``
 method in the extension)::