Correct description in messages; add 'tel' input type

go-back-with-backspace/_locales/en/messages.json

 {
   "extensionName": {
     "message": "Go Back With Backspace",
     "description": "Name of this extension."
   },
   "extensionDescription": {
-    "message": "Restores backspace as a back button.",
+    "message": "Re-enables the backspace key as a back navigation button (except when writing text).",
     "description": "Brief description of this extension."
   }
 }