docs: prefer shorter demo

src/number-keyboard/README.md

@@ -31,12 +31,8 @@ import { Toast } from 'vant';
 export default {
   setup() {
     const show = ref(true);
-    const onInput = (value) => {
-      Toast(value);
-    };
-    const onDelete = () => {
-      Toast('delete');
-    };
+    const onInput = (value) => Toast(value);
+    const onDelete = () => Toast('delete');
 
     return {
       show,

src/number-keyboard/README.zh-CN.md

@@ -37,12 +37,8 @@ import { Toast } from 'vant';
 export default {
   setup() {
     const show = ref(true);
-    const onInput = (value) => {
-      Toast(value);
-    };
-    const onDelete = () => {
-      Toast('删除');
-    };
+    const onInput = (value) => Toast(value);
+    const onDelete = () => Toast('删除');
 
     return {
       show,

src/number-keyboard/demo/index.vue

@@ -137,13 +137,8 @@ export default {
       keyboard: 'default',
     });
 
-    const onInput = (value: string) => {
-      Toast(`${t('input')}: ${value}`);
-    };
-
-    const onDelete = () => {
-      Toast(t('delete'));
-    };
+    const onInput = (value: string) => Toast(`${t('input')}: ${value}`);
+    const onDelete = () => Toast(t('delete'));
 
     return {
       ...toRefs(state),