message: docs(ContactList): use composition api
diff: @@ -26,11 +26,12 @@ app.use(ContactList);
  ```
  ```js
  +import { reactive } from 'vue';
  import { Toast } from 'vant';
  export default {
  - data() {
  - return {
  + setup() {
  + const state = reactive({
  chosenContactId: '1',
  list: [
  {
  @@ -45,18 +46,24 @@ export default {
  tel: '1310000000',
  },
  ],
  - };
  - },
  - methods: {
  - onAdd() {
  + });
  +
  + const onAdd = () => {
  Toast('Add');
  - },
  - onEdit(contact) {
  + };
  + const onEdit = (contact) => {
  Toast('Edit' + contact.id);
  - },
  - onSelect(contact) {
  + };
  + const onSelect = (contact) => {
  Toast('Select' + contact.id);
  - },
  + };
  +
  + return {
  + state,
  + onAdd,
  + onEdit,
  + onSelect,
  + };
  },
  };
  ```
  