Just added also the mark_as_hidden option

Took the opportunity that you were editing them to add it ;)

translations/en-us.all.json

@@ -982,5 +982,9 @@
   {
     "id": "theme_none",
     "translation": "None"
+  },
+  {
+    "id": "mark_as_hidden",
+    "translation": "Mark as Hidden"
   }
 ]