docs: prefer shorter demo

src/submit-bar/README.md

@@ -23,10 +23,7 @@ import { Toast } from 'vant';
 
 export default {
   setup() {
-    const onSubmit = () => {
-      Toast('Submit');
-    };
-
+    const onSubmit = () => Toast('Submit');
     return {
       onSubmit,
     };
@@ -73,13 +70,8 @@ import { Toast } from 'vant';
 
 export default {
   setup() {
-    const onSubmit = () => {
-      Toast('Submit');
-    };
-    const onClickLink = () => {
-      Toast('Click Link');
-    };
-
+    const onSubmit = () => Toast('Submit');
+    const onClickLink = () => Toast('Click Link');
     return {
       onSubmit,
       onClickLink,

src/submit-bar/README.zh-CN.md

@@ -23,10 +23,7 @@ import { Toast } from 'vant';
 
 export default {
   setup() {
-    const onSubmit = () => {
-      Toast('点击按钮');
-    };
-
+    const onSubmit = () => Toast('点击按钮');
     return {
       onSubmit,
     };
@@ -80,13 +77,8 @@ import { Toast } from 'vant';
 
 export default {
   setup() {
-    const onSubmit = () => {
-      Toast('点击按钮');
-    };
-    const onClickLink = () => {
-      Toast('修改地址');
-    };
-
+    const onSubmit = () => Toast('点击按钮');
+    const onClickLink = () => Toast('修改地址');
     return {
       onSubmit,
       onClickLink,

src/submit-bar/demo/index.vue

@@ -71,12 +71,8 @@ export default {
     const t = useTranslate(i18n);
     const checked = ref(true);
 
-    const onSubmit = () => {
-      Toast(t('clickButton'));
-    };
-    const onClickLink = () => {
-      Toast(t('clickLink'));
-    };
+    const onSubmit = () => Toast(t('clickButton'));
+    const onClickLink = () => Toast(t('clickLink'));
 
     return {
       t,