Dialog: update doc

examples/docs/en-US/dialog.md

@@ -239,8 +239,8 @@ If a Dialog is nested in another Dialog, `append-to-body` is required.
 
 :::
 
-### Align in center
-Make the dialog's header & footer align in center
+### Centered content
+Header and footer of Dialog can be centered
 
 :::demo Set `center` to `true` will align dialog's header & footer in center，while the content of it will not, to prevent breaking your own content's layout
 

examples/docs/zh-CN/dialog.md

@@ -237,7 +237,7 @@ Dialog 组件的内容可以是任意的，甚至可以是表格或表单，下
 ### 居中布局
 标题和底部采用居中布局
 
-:::demo 将 `center` 为 `true` 将使标题和底部居中，同时为了防止破坏弹窗内容的布局，内容默认是不局中的
+:::demo 将 `center` 设置为 `true` 即可使标题和底部居中，同时为了防止破坏内容的布局，内容默认是不居中的
 
 ```html
 <el-button type="text" @click="centerDialogVisible = true">点击打开 Dialog</el-button>