docs: 菜单自定义图标demo增加子组件

src/packages/__VUE/menu/doc.en-US.md

@@ -233,6 +233,10 @@ import { reactive, ref } from 'vue';
 import { TriangleDown, Checked } from '@nutui/icons-vue';
 
 export default {
+  components: {
+    TriangleDown,
+    Checked
+  },
   setup() {
     const state = reactive({
       options1: [

src/packages/__VUE/menu/doc.md

@@ -234,6 +234,10 @@ import { reactive, ref } from 'vue';
 import { TriangleDown, Checked } from '@nutui/icons-vue';
 
 export default {
+  components: {
+    TriangleDown,
+    Checked
+  },
   setup() {
     const state = reactive({
       options1: [

src/packages/__VUE/menu/doc.taro.md

@@ -234,6 +234,10 @@ import { reactive, ref } from 'vue';
 import { TriangleDown, Checked } from '@nutui/icons-vue-taro';
 
 export default {
+  components: {
+    TriangleDown,
+    Checked
+  },
   setup() {
     const state = reactive({
       options1: [