feature #291 Mention what you should throw in your UserProvider (weaverryan)

This PR was squashed before being merged into the 1.0-dev branch (closes #291).

Discussion
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Mention what you should throw in your UserProvider

A tip from @iltar to make things more clear :)

Commits
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9fc3698 Mention what you should throw in your UserProvider

Author: weaverryan

src/Resources/skeleton/security/UserProvider.tpl.php

@@ -17,6 +17,8 @@ class <?= $class_name ?> implements UserProviderInterface
      * this method.
      *
      * @return UserInterface
+     *
+     * @throws UsernameNotFoundException if the user is not found
      */
     public function loadUserByUsername($username)
     {
@@ -46,8 +48,6 @@ public function refreshUser(UserInterface $user)
             throw new UnsupportedUserException(sprintf('Invalid user class "%s".', get_class($user)));
         }
 
-        /* @var <?= $user_short_name ?> $user */
-
         // Return a User object after making sure its data is "fresh".
         // Or throw a UsernameNotFoundException if the user no longer exists.
         throw new \Exception('TODO: fill in refreshUser() inside '.__FILE__);