Fix example in Regex.rst

Author: nclavaud

reference/constraints/Regex.rst

@@ -244,7 +244,7 @@ need to specify the HTML5 compatible pattern in the ``htmlPattern`` option:
         {
             #[Assert\Regex(
                 pattern: '/^[a-z]+$/i',
-                match: '^[a-zA-Z]+$'
+                htmlPattern: '^[a-zA-Z]+$'
             )]
             protected $name;
         }