fix: icon error

components/button/demo/button-group.md

@@ -19,7 +19,7 @@ The `size` can be set to `large`, `small` or left unset resulting in a default s
 
 ```jsx
 import { Button } from 'antd';
-import { Left, Right } from '@ant-design/icons';
+import { Left, Right, Cloud, CloudDownload } from '@ant-design/icons';
 
 const ButtonGroup = Button.Group;
 
@@ -53,12 +53,12 @@ ReactDOM.render(
       </Button>
     </ButtonGroup>
     <ButtonGroup>
-      <Button type="primary" icon="cloud" />
-      <Button type="primary" icon="cloud-download" />
+      <Button type="primary" icon={<Cloud />} />
+      <Button type="primary" icon={<CloudDownload />} />
     </ButtonGroup>
     <ButtonGroup>
-      <Button type="primary" size="small" icon="cloud" />
-      <Button type="primary" size="small" icon="cloud-download" />
+      <Button type="primary" size="small" icon={<Cloud />} />
+      <Button type="primary" size="small" icon={<CloudDownload />} />
     </ButtonGroup>
   </div>,
   mountNode,

components/form/demo/form-context.md

@@ -15,7 +15,7 @@ Use `Form.Provider` to process data between forms. In this case, submit button i
 
 ```tsx
 import { Form, Input, InputNumber, Modal, Button, Avatar, Typography } from 'antd';
-import { Smile } from '@ant-design/icons';
+import { Smile, User } from '@ant-design/icons';
 
 const layout = {
   labelCol: { span: 8 },
@@ -96,7 +96,7 @@ const Demo = () => {
                 <ul>
                   {users.map((user, index) => (
                     <li key={index} className="user">
-                      <Avatar icon="user" />
+                      <Avatar icon={<User />} />
                       {user.name} - {user.age}
                     </li>
                   ))}