adding missing const

frontend/lib/modules/new_trip_location_search.dart

@@ -21,7 +21,7 @@ const Map<String, List> debugLocations = {
 class NewTripLocationSearch extends StatefulWidget {
   Future<SharedPreferences> prefs = SharedPreferences.getInstance();
   Trip trip;
-  
+
   NewTripLocationSearch(
     this.trip,
   );
@@ -71,13 +71,13 @@ class _NewTripLocationSearchState extends State<NewTripLocationSearch> {
     hintText: 'Enter a city name or long press on the map.',
     onSubmitted: setTripLocation,
     controller: _controller,
-    leading: Icon(Icons.search),
+    leading: const Icon(Icons.search),
     trailing: [
       ElevatedButton(
         onPressed: () {
           setTripLocation(_controller.text);
         },
-        child: Text('Search'),
+        child: const Text('Search'),
       )
     ]
   );
@@ -97,7 +97,7 @@ class _NewTripLocationSearchState extends State<NewTripLocationSearch> {
         )
       );
     },
-    child: Text('Use current location'),
+    child: const Text('Use current location'),
   );
 
   @override