refactor: Enable more strict lints

lib/pages/chat_list/chat_list.dart

@@ -78,7 +78,7 @@ class ChatListController extends State<ChatList>
   String? _activeSpaceId;
   String? get activeSpaceId => _activeSpaceId;
 
-  void setActiveSpace(String spaceId) async {
+  Future<void> setActiveSpace(String spaceId) async {
     await Matrix.of(context).client.getRoomById(spaceId)!.postLoad();
 
     setState(() {
@@ -90,7 +90,7 @@ class ChatListController extends State<ChatList>
     _activeSpaceId = null;
   });
 
-  void onChatTap(Room room) async {
+  Future<void> onChatTap(Room room) async {
     if (room.membership == Membership.invite) {
       final joinResult = await showFutureLoadingDialog(
         context: context,
@@ -156,7 +156,7 @@ class ChatListController extends State<ChatList>
   bool isSearching = false;
   static const String _serverStoreNamespace = 'im.fluffychat.search.server';
 
-  void setServer() async {
+  Future<void> setServer() async {
     final newServer = await showTextInputDialog(
       useRootNavigator: false,
       title: L10n.of(context).changeTheHomeserver,
@@ -184,7 +184,7 @@ class ChatListController extends State<ChatList>
   final TextEditingController searchController = TextEditingController();
   final FocusNode searchFocusNode = FocusNode();
 
-  void _search() async {
+  Future<void> _search() async {
     final client = Matrix.of(context).client;
     if (!isSearching) {
       setState(() {
@@ -292,7 +292,7 @@ class ChatListController extends State<ChatList>
     }
   }
 
-  void editSpace(BuildContext context, String spaceId) async {
+  Future<void> editSpace(BuildContext context, String spaceId) async {
     await Matrix.of(context).client.getRoomById(spaceId)!.postLoad();
     if (mounted) {
       context.push('/rooms/$spaceId/details');
@@ -326,7 +326,7 @@ class ChatListController extends State<ChatList>
     );
   }
 
-  void _processIncomingUris(Uri? uri) async {
+  Future<void> _processIncomingUris(Uri? uri) async {
     if (uri == null) return;
     context.go('/rooms');
     WidgetsBinding.instance.addPostFrameCallback((_) {
@@ -399,7 +399,7 @@ class ChatListController extends State<ChatList>
     super.dispose();
   }
 
-  void chatContextAction(
+  Future<void> chatContextAction(
     Room room,
     BuildContext posContext, [
     Room? space,
@@ -671,7 +671,7 @@ class ChatListController extends State<ChatList>
     }
   }
 
-  void dismissStatusList() async {
+  Future<void> dismissStatusList() async {
     final result = await showOkCancelAlertDialog(
       title: L10n.of(context).hidePresences,
       context: context,
@@ -682,7 +682,7 @@ class ChatListController extends State<ChatList>
     }
   }
 
-  void setStatus() async {
+  Future<void> setStatus() async {
     final client = Matrix.of(context).client;
     final currentPresence = await client.fetchCurrentPresence(client.userID!);
     final input = await showTextInputDialog(
@@ -793,7 +793,10 @@ class ChatListController extends State<ChatList>
     });
   }
 
-  void editBundlesForAccount(String? userId, String? activeBundle) async {
+  Future<void> editBundlesForAccount(
+    String? userId,
+    String? activeBundle,
+  ) async {
     final l10n = L10n.of(context);
     final client = Matrix.of(
       context,

lib/pages/chat_list/client_chooser_button.dart

@@ -194,7 +194,7 @@ class ClientChooserButton extends StatelessWidget {
     );
   }
 
-  void _clientSelected(Object object, BuildContext context) async {
+  Future<void> _clientSelected(Object object, BuildContext context) async {
     if (object is Client) {
       controller.setActiveClient(object);
     } else if (object is String) {

lib/pages/chat_list/search_title.dart

@@ -52,7 +52,7 @@ class SearchTitle extends StatelessWidget {
                     Expanded(
                       child: Align(
                         alignment: Alignment.centerRight,
-                        child: trailing!,
+                        child: trailing,
                       ),
                     ),
                 ],

lib/pages/chat_list/space_view.dart

@@ -60,7 +60,7 @@ class _SpaceViewState extends State<SpaceView> {
     super.initState();
   }
 
-  void _loadHierarchy() async {
+  Future<void> _loadHierarchy() async {
     final matrix = Matrix.of(context);
     final room = matrix.client.getRoomById(widget.spaceId);
     if (room == null) return;
@@ -127,7 +127,7 @@ class _SpaceViewState extends State<SpaceView> {
     }
   }
 
-  void _joinChildRoom(SpaceRoomsChunk$2 item) async {
+  Future<void> _joinChildRoom(SpaceRoomsChunk$2 item) async {
     final client = Matrix.of(context).client;
     final space = client.getRoomById(widget.spaceId);
     final via = space?.spaceChildren
@@ -146,7 +146,7 @@ class _SpaceViewState extends State<SpaceView> {
     if (room != null) widget.onChatTab(room);
   }
 
-  void _onSpaceAction(SpaceActions action) async {
+  Future<void> _onSpaceAction(SpaceActions action) async {
     final space = Matrix.of(context).client.getRoomById(widget.spaceId);
 
     switch (action) {
@@ -184,7 +184,7 @@ class _SpaceViewState extends State<SpaceView> {
     }
   }
 
-  void _addChatOrSubspace(AddRoomType roomType) async {
+  Future<void> _addChatOrSubspace(AddRoomType roomType) async {
     final names = await showTextInputDialog(
       context: context,
       title: roomType == AddRoomType.subspace
@@ -261,7 +261,10 @@ class _SpaceViewState extends State<SpaceView> {
     _loadHierarchy();
   }
 
-  void _showSpaceChildEditMenu(BuildContext posContext, String roomId) async {
+  Future<void> _showSpaceChildEditMenu(
+    BuildContext posContext,
+    String roomId,
+  ) async {
     final overlay =
         Overlay.of(posContext).context.findRenderObject() as RenderBox;