update tree-view example to add v-for key

chrisvfritz · Jinjiang · commit 7cf68a3c8e0f · 2018-02-01T15:47:18.000+08:00
diff --git a/src/v2/examples/tree-view.md b/src/v2/examples/tree-view.md
@@ -6,4 +6,4 @@ order: 4
 
 > 本示例是一个简单的树形视图实现，它展现了组件的递归使用。
 
-<iframe width="100%" height="500" src="https://jsfiddle.net/yyx990803/3p0j5sgy/embedded/result,html,js,css" allowfullscreen="allowfullscreen" frameborder="0"></iframe>
+<iframe width="100%" height="500" src="https://jsfiddle.net/chrisvfritz/pnqzspoe/embedded/result,html,js,css" allowfullscreen="allowfullscreen" frameborder="0"></iframe>

Original file line number	Diff line number	Diff line change
`@@ -6,4 +6,4 @@ order: 4`
`6`	`6`
`7`	`7`	`> 本示例是一个简单的树形视图实现，它展现了组件的递归使用。`
`8`	`8`
`9`		`-<iframe width="100%" height="500" src="https://jsfiddle.net/yyx990803/3p0j5sgy/embedded/result,html,js,css" allowfullscreen="allowfullscreen" frameborder="0"></iframe>`
	`9`	`+<iframe width="100%" height="500" src="https://jsfiddle.net/chrisvfritz/pnqzspoe/embedded/result,html,js,css" allowfullscreen="allowfullscreen" frameborder="0"></iframe>`