docs: prefer shorter demo

src/rate/README.md

@@ -95,9 +95,7 @@ import { Toast } from 'vant';
 export default {
   setup() {
     const value = ref(3);
-    const onChange = (value) => {
-      Toast('current value:' + value);
-    };
+    const onChange = (value) => Toast('current value:' + value);
     return {
       value,
       onChange,

src/rate/README.zh-CN.md

@@ -99,9 +99,7 @@ import { Toast } from 'vant';
 export default {
   setup() {
     const value = ref(3);
-    const onChange = (value) => {
-      Toast('当前值：' + value);
-    };
+    const onChange = (value) => Toast('当前值：' + value);
     return {
       value,
       onChange,

src/rate/demo/index.vue

@@ -85,9 +85,7 @@ export default {
       value7: 2,
     });
 
-    const onChange = (value) => {
-      Toast(t('toastContent', value));
-    };
+    const onChange = (value) => Toast(t('toastContent', value));
 
     return {
       ...toRefs(state),