Add indicator for processed messages

config/locales/en.yml

@@ -48,6 +48,7 @@ en:
         name: "Name"
       message:
         author: "Author"
+        processed: "Processed?"
         text: "Content"
         time: "Time"
       puzzle:
@@ -64,7 +65,7 @@ en:
         completion:
           attributes:
             display_time_from_start:
-              invalid: "Allowed formats: xx:xx:xx, x:xx:xx, xx:xx, x:xx"
+              invalid: "Allowed formats: xx:xx:xx, x:xx:xx, xx:xx, x:xx, xx"
             puzzle_id:
               taken: "This contestant has already completed this puzzle"
         csv_import: