fix a error style

2017/08/24.md

@@ -137,7 +137,8 @@ interface Square extends Shape, PenStroke {
 ## Redux-form
 
 * 首先需要将 `formReducer` 和自己其他的reducer合并在一起。
-``` javascript
+
+```javascript
 import { createStore, combineReducers } from 'redux'
 import { reducer as formReducer } from 'redux-form'