message: docs(ContactEdit): use composition api
diff: @@ -26,21 +26,24 @@ app.use(ContactEdit);
  ```
  ```js
  +import { ref } from 'vue';
  import { Toast } from 'vant';
  export default {
  - data() {
  - return {
  - editingContact: {},
  - };
  - },
  - methods: {
  - onSave(contactInfo) {
  + setup() {
  + const editingContact = ref({});
  + const onSave = (contactInfo) => {
  Toast('Save');
  - },
  - onDelete(contactInfo) {
  + };
  + const onDelete = (contactInfo) => {
  Toast('Delete');
  - },
  + };
  +
  + return {
  + onSave,
  + onDelete,
  + editingContact,
  + };
  },
  };
  ```
  