use regex for commands

lib/src/message_input.dart

@@ -206,7 +206,7 @@ class _MessageInputState extends State<MessageInput> {
         .channel
         .config
         .commands
-        .where((c) => c.name.startsWith(text.replaceFirst('/', '')))
+        .where((c) => c.name.contains(text.replaceFirst('/', '')))
         .toList();
 
     RenderBox renderBox = context.findRenderObject();

lib/stream_chat_flutter.dart

@@ -8,6 +8,7 @@ export 'src/channel_preview.dart';
 export 'src/message_input.dart';
 export 'src/message_list_view.dart';
 export 'src/message_widget.dart';
+export 'src/reaction_picker.dart';
 export 'src/stream_channel.dart';
 export 'src/stream_chat.dart';
 export 'src/stream_chat_theme.dart';