remove trailing whitespace. [ci skip]

activerecord/lib/active_record/persistence.rb

@@ -430,7 +430,7 @@ def reload(options = nil)
       self
     end
 
-    # Saves the record with the updated_at/on attributes set to the current time 
+    # Saves the record with the updated_at/on attributes set to the current time
     # or the time specified.
     # Please note that no validation is performed and only the +after_touch+,
     # +after_commit+ and +after_rollback+ callbacks are executed.