[ticket/14247] Use quotes around @ and % strings in YAML

PHPBB3-14247

phpBB/config/default/container/services_user.yml

@@ -2,19 +2,19 @@ services:
     acl.permissions:
         class: phpbb\permissions
         arguments:
-            - @dispatcher
-            - @user
+            - '@dispatcher'
+            - '@user'
 
     user:
         class: phpbb\user
         arguments:
-            - @language
-            - %datetime.class%
+            - '@language'
+            - '%datetime.class%'
 
     user_loader:
         class: phpbb\user_loader
         arguments:
-            - @dbal.conn
-            - %core.root_path%
-            - %core.php_ext%
-            - %tables.users%
+            - '@dbal.conn'
+            - '%core.root_path%'
+            - '%core.php_ext%'
+            - '%tables.users%'