Add localized message to feature index output for 'No features found'

src/_locales/en/messages.json

@@ -156,5 +156,8 @@
   },
   "popupZoom": {
     "message": "Zoom to here"
+  },
+  "fIndexNoFeatures": {
+    "message": "No features found"
   }
 }

src/_locales/fr/messages.json

@@ -156,5 +156,8 @@
   },
   "popupZoom": {
     "message": "Zoomer ici"
+  },
+  "fIndexNoFeatures": {
+    "message": "Aucun élément géographique trouvé"
   }
 }

src/_locales/sv/messages.json

@@ -123,5 +123,8 @@
   },
   "popupZoom": {
     "message": "Zooma hit"
+  },
+  "fIndexNoFeatures": {
+    "message": "Inget geografiskt objekt hittades"
   }
 }

src/content.js

@@ -25,7 +25,7 @@ document.addEventListener("readystatechange", () => {
         "kbdShortcuts", "kbdMovement", "kbdFeature", "kbdPanUp", "kbdPanDown", 
         "kbdPanLeft", "kbdPanRight", "kbdPanIncrement", "kbdZoom", 
         "kbdPrevFeature", "kbdNextFeature", "dfLayer", "dfPastedLayer",
-        "popupZoom"
+        "popupZoom","fIndexNoFeatures"
       ];
 
       options.locale = {};