Update best_practices.rst

Author: 94noni

best_practices.rst

@@ -378,7 +378,8 @@ Use Voters to Implement Fine-grained Security Restrictions
 
 If your security logic is complex, you should create custom
 :doc:`security voters </security/voters>` instead of defining long expressions
-inside the ``@Security`` annotation.
+inside the ``Security`` attribute
+(or annotation if your PHP version doesn't support attributes yet).
 
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