Change generic comment syntax to real generic syntax.

lib/src/stream_queue.dart

Index: lib/src/stream_queue.dart
diff --git a/lib/src/stream_queue.dart b/lib/src/stream_queue.dart
index 14eb7a0a66f6b29e48b2da2bed9010c235561fd4..217032656492dcece2f641810b94748647e0d67b 100644
--- a/lib/src/stream_queue.dart
+++ b/lib/src/stream_queue.dart
@@ -353,10 +353,10 @@ abstract class StreamQueue<T> {
   /// CancelableOperation<String> nextStdinLine() =>
   ///     _stdinQueue.cancelable((queue) => queue.next);
   /// ```
-  CancelableOperation/*<S>*/ cancelable/*<S>*/(
-      Future/*<S>*/ callback(StreamQueue<T> queue)) {
+  CancelableOperation<S> cancelable<S>(
+      Future<S> callback(StreamQueue<T> queue)) {
     var transaction = startTransaction();
-    var completer = new CancelableCompleter/*<S>*/(onCancel: () {
+    var completer = new CancelableCompleter<S>(onCancel: () {
       transaction.reject();
     });