Fix typo in enum twig doc functions

doc/functions/enum.rst

@@ -13,10 +13,12 @@
     {{ enum('App\\MyEnum').SomeCase.value }}
 
     {# get all cases of an enum #}
-    {% enum('App\\MyEnum').cases %}
+    {% for case in enum('App\\MyEnum').cases %}
+        {{ case.value }}
+    {% endfor %}
 
     {# call any methods of the enum class #}
-    {% enum('App\\MyEnum').someMethod() %}
+    {{ enum('App\\MyEnum').someMethod() }}
 
 When using a string literal for the ``enum`` argument, it will be validated during compile time to be a valid enum name.