minor #11511 use code block bash instead of php (OskarStark)

This PR was merged into the 3.4 branch.

Discussion
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use code block bash instead of php

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Commits
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7237d24 use code block bash instead of php

Author: javiereguiluz

components/phpunit_bridge.rst

@@ -254,10 +254,12 @@ By default, the PHPUnit Bridge displays only deprecation messages.
 To show the full stack trace related to a deprecation, set the value of ``SYMFONY_DEPRECATIONS_HELPER``
 to a regular expression matching the deprecation message.
 
-For example, if the following deprecation notice is thrown::
+For example, if the following deprecation notice is thrown:
 
-    1x: Doctrine\Common\ClassLoader is deprecated.
-      1x in EntityTypeTest::setUp from Symfony\Bridge\Doctrine\Tests\Form\Type
+    .. code-block:: bash
+
+        1x: Doctrine\Common\ClassLoader is deprecated.
+          1x in EntityTypeTest::setUp from Symfony\Bridge\Doctrine\Tests\Form\Type
 
 Running the following command will display the full stack trace: