kernel.debug is a boolean, not a string

Author: OskarStark

reference/configuration/twig.rst

@@ -174,7 +174,7 @@ specific timezone is passed as argument.
 debug
 ~~~~~
 
-**type**: ``boolean`` **default**: ``'%kernel.debug%'``
+**type**: ``boolean`` **default**: ``%kernel.debug%``
 
 If ``true``, the compiled templates include a ``__toString()`` method that can
 be used to display their nodes.