fix dart format. (#321)

Author: cloudwebrtc

lib/src/options.dart

@@ -19,7 +19,7 @@ class TrackOption<E extends Object, T extends Object> {
 /// This will enable the local participant to publish tracks on connect,
 /// instead of having to explicitly publish them.
 /// Defaults to false for all three tracks: microphone, camera, and screen.
-/// You can also create LocalAudio/VideoTrack on your `PreJoin` page 
+/// You can also create LocalAudio/VideoTrack on your `PreJoin` page
 /// (preview camera or select audio device), Automatically publish these
 /// tracks after the room is connected.
 class FastConnectOptions {