fix spelling in core libraries

sdk/lib/async/stream_transformers.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart.async;
 
 /**
  * Wraps an [_EventSink] so it exposes only the [EventSink] interface.
  */
 class _EventSinkWrapper<T> implements EventSink<T> {
@@ skipping 252 matching lines @@
 
 /// A closure mapping a stream and cancelOnError to a StreamSubscription.
 typedef StreamSubscription<T> _SubscriptionTransformer<S, T>(
     Stream<S> stream, bool cancelOnError);
 
 /**
  * A [StreamTransformer] that minimizes the number of additional classes.
  *
  * Instead of implementing three classes: a [StreamTransformer], a [Stream]
  * (as the result of a `bind` call) and a [StreamSubscription] (which does the
- * actual work), this class only requires a fincution that is invoked when the
+ * actual work), this class only requires a function that is invoked when the
  * last bit (the subscription) of the transformer-workflow is needed.
  *
  * The given transformer function maps from Stream and cancelOnError to a
  * `StreamSubscription`. As such it can also act on `cancel` events, making it
  * fully general.
  */
 class _StreamSubscriptionTransformer<S, T> implements StreamTransformer<S, T> {
   final _SubscriptionTransformer<S, T> _transformer;
 
   const _StreamSubscriptionTransformer(this._transformer);
@@ skipping 20 matching lines @@
                                  void onDone(),
                                  bool cancelOnError }) {
     cancelOnError = identical(true, cancelOnError);
     StreamSubscription<T> result = _transformer(_stream, cancelOnError);
     result.onData(onData);
     result.onError(onError);
     result.onDone(onDone);
     return result;
   }
 }