chore: uni-app 二级菜单添加 uts 分类

docs/.vuepress/config/navbar.js

@@ -37,6 +37,11 @@ export const navbar = [
         type: 'link',
         link: '/api/'
       },
+      {
+        text: 'UTS',
+        type: 'link',
+        link: '/uni-app-x/uts/'
+      },
       {
         text: '插件',
         type: 'link',