Merge pull request DrkSephy#80 from ShredderMing/master

Fix generator next example (README_zhCn.md)

Author: DrkSephy

README_zhCn.md

@@ -937,11 +937,10 @@ function* sillyGenerator() {
 }
 
 var generator = sillyGenerator();
-var value = generator.next();
-> console.log(value); // { value: 1, done: false }
-> console.log(value); // { value: 2, done: false }
-> console.log(value); // { value: 3, done: false }
-> console.log(value); // { value: 4, done: false }
+> console.log(generator.next()); // { value: 1, done: false }
+> console.log(generator.next()); // { value: 2, done: false }
+> console.log(generator.next()); // { value: 3, done: false }
+> console.log(generator.next()); // { value: 4, done: false }
 ```
 
 就像上面的例子，当[next](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Generator/next)运行时，它会把我们的generator向前“推动”，同时执行新的表达式。