Typo: Update rememberme.adoc

I changed 'unecessarily' to 'unnecessarily'

docs/modules/ROOT/pages/servlet/authentication/rememberme.adoc

@@ -50,7 +50,7 @@ If you have more than one in your application context, you need to specify which
 
 [[remember-me-persistent-token]]
 == Persistent Token Approach
-This approach is based on the article titled http://jaspan.com/improved_persistent_login_cookie_best_practice[http://jaspan.com/improved_persistent_login_cookie_best_practice], with some minor modifications. (Essentially, the username is not included in the cookie, to prevent exposing a valid login name unecessarily.
+This approach is based on the article titled http://jaspan.com/improved_persistent_login_cookie_best_practice[http://jaspan.com/improved_persistent_login_cookie_best_practice], with some minor modifications. (Essentially, the username is not included in the cookie, to prevent exposing a valid login name unnecessarily.
 There is a discussion on this in the comments section of this article.)
 To use the this approach with namespace configuration, supply a datasource reference: