Merge pull request #4961 from iamchenxin/en_docs

[docs] Fix syntac error

docs/docs/10.1-animation.md

@@ -122,23 +122,23 @@ It is also possible to use custom class names for each of the steps in your tran
 ```javascript
   ...
   <ReactCSSTransitionGroup
-    transitionName={{
+    transitionName={ {
       enter: 'enter',
       enterActive: 'enterActive',
       leave: 'leave',
       leaveActive: 'leaveActive',
       appear: 'appear',
       appearActive: 'appearActive'
-    }}>
+    } }>
     {item}
   </ReactCSSTransitionGroup>
 
   <ReactCSSTransitionGroup
-    transitionName={{
+    transitionName={ {
       enter: 'enter',
       leave: 'leave',
       appear: 'appear'
-    }}>
+    } }>
     {item2}
   </ReactCSSTransitionGroup>
   ...