fix(trip-basics-pane.js): Add warning when navigating away from unsav…

…ed trip changes

resolve typos, remove string assembly for internationalization

lib/components/user/monitored-trip/trip-basics-pane.js

@@ -104,9 +104,9 @@ class TripBasicsPane extends Component {
     // but don't show it when they click submit or cancel.
     const unsavedChanges = dirty && !isSubmitting && !canceled
     // Message changes depending on if the new or existing trip is being edited
-    const unsavedChangesMessage = `You have haven't saved your ${
-      isCreating ? 'new ' : ''
-    }trip yet. If you leave, ${isCreating ? 'it' : 'changes'} will be lost.`
+    const unsavedChangesNewTripMessage = 'You haven\'t saved your new trip yet. If you leave, it will be lost.'
+    const unsavedChangesExistingTripMessage = 'You haven\'t saved your trip yet. If you leave, changes will be lost.'
+    const unsavedChangesMessage = isCreating ? unsavedChangesNewTripMessage : unsavedChangesExistingTripMessage
 
     if (!itinerary) {
       return <div>No itinerary to display.</div>