Move some translations of invoice and bill to documents langugage file

resources/lang/en-GB/documents.php

@@ -0,0 +1,12 @@
+<?php
+
+return [
+    'messages' => [
+        'email_sent'        => ':type email has been sent!',
+        'marked_sent'       => ':type marked as sent!',
+        'marked_paid'       => ':type marked as paid!',
+        'marked_viewed'     => ':type marked as viewed!',
+        'marked_cancelled'  => ':type marked as cancelled!',
+        'marked_received'   => ':type marked as received!',
+    ],
+];