fix Singleton link in readme, fix some typo

Author: senghoo

Diff for: README.md

@@ -7,11 +7,11 @@ Go 语言设计模式的实例代码
 ## 创建型模式
 
 * [简单工厂模式（Simple Factory）](https://github.com/senghoo/golang-design-pattern/tree/master/00_simple_factory)
-* [厂方法模式（Factory Method）](https://github.com/senghoo/golang-design-pattern/tree/master/04_factory_method)
+* [工厂方法模式（Factory Method）](https://github.com/senghoo/golang-design-pattern/tree/master/04_factory_method)
 * [抽象工厂模式（Abstract Factory）](https://github.com/senghoo/golang-design-pattern/tree/master/05_abstract_factory)
 * [创建者模式（Builder）](https://github.com/senghoo/golang-design-pattern/tree/master/06_builder)
 * [原型模式（Prototype）](https://github.com/senghoo/golang-design-pattern/tree/master/07_prototype)
-* [单例模式（Singleton）](https://github.com/senghoo/golang-design-pattern/tree/master/02_adapter)
+* [单例模式（Singleton）](https://github.com/senghoo/golang-design-pattern/tree/master/03_singleton)
 
 ## 结构型模式