fix Bug or add docs

src/components/LoadingContent/index.ts

@@ -0,0 +1,3 @@
+import LoadingContent from './index.vue';
+
+export { LoadingContent };

src/components/LoadingContent/index.vue

@@ -0,0 +1,12 @@
+<template></template>
+<script lang="ts">
+  import { useLoadingBar } from 'naive-ui';
+
+  export default {
+    name: 'LoadingContent',
+    setup() {
+      //挂载在 window 方便与在js中使用
+      window['$loading'] = useLoadingBar();
+    },
+  };
+</script>