minor #11037 removed php open tag (OskarStark)

This PR was merged into the 3.4 branch.

Discussion
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removed php open tag

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Commits
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b64f784 removed php open tag

Author: javiereguiluz

bundles/best_practices.rst

@@ -224,7 +224,6 @@ following standardized instructions in your ``README.md`` file.
         in the `app/AppKernel.php` file of your project:
 
         ```php
-        <?php
         // app/AppKernel.php
 
         // ...