Indicate that cookie_secure is false by default

Closes symfony/issues#31376

Author: junowilderness

reference/configuration/framework.rst

@@ -875,11 +875,11 @@ The possible values for this option are:
 cookie_secure
 .............
 
-**type**: ``boolean`` or ``string`` **default**: ``'auto'``
+**type**: ``boolean`` or ``string`` **default**: ``false``
 
-This determines whether cookies should only be sent over secure connections. The
-default value is ``auto``, which means ``true`` for HTTPS requests and ``false``
-for HTTP requests.
+This determines whether cookies should only be sent over secure connections.
+Setting this value to ``auto`` means ``true`` for HTTPS requests and ``false`` for
+HTTP requests.
 
 cookie_httponly
 ...............