Add missing comma in array

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.4
| Fixed tickets |

components/expression_language/syntax.rst

@@ -259,7 +259,7 @@ For example::
     $inGroup = $language->evaluate(
         'user.group in ["human_resources", "marketing"]',
         array(
-            'user' => $user
+            'user' => $user,
         )
     );