minor #12734 Fix documentation for PhpUnitBridge regex configuration (MrYamous)

This PR was merged into the 4.3 branch.

Discussion
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Fix documentation for PhpUnitBridge regex configuration

PR for issue #12726

According to comments in symfony/symfony#34693, documentation appears to have diverged between 4.2 and 4.3.
Restoring the correct syntax in 4.3 documentation.

Commits
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d76b6d0 Fix documentation for PhpUnitBridge regex configuration

Author: javiereguiluz

components/phpunit_bridge.rst

@@ -209,7 +209,7 @@ message, enclosed with ``/``. For example, with:
 
         <php>
             <server name="KERNEL_CLASS" value="App\Kernel"/>
-            <env name="SYMFONY_DEPRECATIONS_HELPER" value="regex=/foobar/"/>
+            <env name="SYMFONY_DEPRECATIONS_HELPER" value="/foobar/"/>
         </php>
     </phpunit>