chore: fix some linter warnings

lib/main.dart

@@ -140,9 +140,6 @@ class _ChooseStationPageState extends State<ChooseStationPage> {
       maxStations: 20,
     );
   }
-  /* TODO: function to get stations along a vehicles route past current station,
-  *   and run the correct function on switching to the screen
-  */
 
   void findStationsByName(
     String name, {
@@ -151,8 +148,8 @@ class _ChooseStationPageState extends State<ChooseStationPage> {
     stationList = await ApiHandler.findStations(name);
   }
 
-  void showResult(Future<List<Station>> future_id) async {
-    stationList = await future_id;
+  void showResult(Future<List<Station>> futureId) async {
+    stationList = await futureId;
     setState(() {});
   }
 
@@ -235,7 +232,6 @@ class ChooseDeparturePage extends StatefulWidget {
 
 class _ChooseDeparturePageState extends State<ChooseDeparturePage> {
   List<Departure> departureList = [];
-  Departure? _selectedDeparture;
 
   void loadDepartures(Station startStation) async {
     departureList = await ApiHandler.departures(startStation.id);
@@ -244,6 +240,7 @@ class _ChooseDeparturePageState extends State<ChooseDeparturePage> {
 
   @override
   initState() {
+    super.initState();
     loadDepartures(widget.startStation);
   }
 
@@ -300,7 +297,7 @@ class DepartureList extends StatelessWidget {
   final List<Departure> departureList;
   final ValueChanged<Departure> onTapped;
 
-  DepartureList({
+  const DepartureList({
     required this.departureList,
     required this.onTapped,
   });
@@ -348,6 +345,7 @@ class _ChooseArrivalPageState extends State<ChooseArrivalPage> {
 
   @override
   initState() {
+    super.initState();
     loadArrivals(widget.departure.ref);
   }
 
@@ -398,7 +396,7 @@ class _ChooseArrivalPageState extends State<ChooseArrivalPage> {
       Journey journey = await Journey.fromSegment(newSegment);
       journeyId = journey.id as int;
     } else {
-      Segment segment = await newSegment;
+      Segment segment = newSegment;
       Journey.dbAppendJourneySegment(
         widget.journeyId as int,
         segment.id as int,