Update security.rst

Fixed the mistype.

Author: profuel

security.rst

@@ -2686,7 +2686,7 @@ Frequently Asked Questions
     Sometimes authentication may be successful, but after redirecting, you're
     logged out immediately due to a problem loading the ``User`` from the session.
     To see if this is an issue, check your log file (``var/log/dev.log``) for
-    the log message:
+    the log message.
 
 **Cannot refresh token because user has changed**
     If you see this, there are two possible causes. First, there may be a problem