Translate unknown call state

Signed-off-by: Šimon Brandner <simon.bra.ag@gmail.com>

src/components/views/messages/CallEvent.tsx

@@ -148,10 +148,9 @@ export default class CallEvent extends React.Component<IProps, IState> {
             );
         }
 
-        // XXX: Should we translate this?
         return (
             <div className="mx_CallEvent_content">
-                { "The call is in an unknown state!" }
+                { _t("The call is in an unknown state!") }
             </div>
         );
     }

src/i18n/strings/en_EN.json

@@ -1810,6 +1810,7 @@
     "This call has failed": "This call has failed",
     "You missed this call": "You missed this call",
     "Call back": "Call back",
+    "The call is in an unknown state!": "The call is in an unknown state!",
     "Sunday": "Sunday",
     "Monday": "Monday",
     "Tuesday": "Tuesday",