docs(Empty): use composition api

src/empty/demo/index.vue

@@ -34,9 +34,11 @@
   </demo-block>
 </template>
 
-<script>
+<script lang="ts">
-export default {
+import { ref } from 'vue';
-  i18n: {
+import { useTranslate } from '@demo/use-translate';
+
+const i18n = {
   'zh-CN': {
     error: '通用错误',
     search: '搜索提示',
@@ -55,11 +57,16 @@ export default {
     customImage: 'Custom Image',
     bottomContent: 'Bottom Content',
   },
-  },
+};
+
+export default {
+  setup() {
+    const t = useTranslate(i18n);
+    const active = ref('error');
 
-  data() {
     return {
-      active: 'error',
+      t,
+      active,
     };
   },
 };