Update charted to 0.4.8 and roll

packages/quiver/lib/src/iterables/count.dart

 // Copyright 2013 Google Inc. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 part of quiver.iterables;
 
-/**
- * Returns an infinite [Iterable] of [num]s, starting from [start] and
- * increasing by [step].
- */
+/// Returns an infinite [Iterable] of [num]s, starting from [start] and
+/// increasing by [step].
 Iterable<num> count([num start = 0, num step = 1]) => new _Count(start, step);
 
 class _Count extends InfiniteIterable<num> {
   final num start, step;
 
   _Count(num this.start, num this.step);
 
   Iterator<num> get iterator => new _CountIterator(start, step);
 
   // TODO(justin): return an infinite list for toList() and a special Set
   // implmentation for toSet()?
 }
 
 class _CountIterator implements Iterator<num> {
   final num _start, _step;
   num _current;
 
   _CountIterator(num this._start, this._step);
 
   num get current => _current;
 
   bool moveNext() {
     _current = (_current == null) ? _start : _current + _step;
     return true;
   }
 }