Fix the import issue

Author: jchen042

README.md

@@ -21,10 +21,16 @@ For example:
 
 ```js
 // You can import any component you want as a named export from 'vue-virtualised'. e.g.
-import { VirtualisedList, VirtualisedTree } from 'vue-virtualised';
+import { VirtualisedList, VirtualisedTree } from "vue-virtualised";
 
 // Or you can import the component as a named export. e.g.
-import { VirtualisedTree as Tree } from 'vue-virtualised';
+import { VirtualisedTree as Tree } from "vue-virtualised";
+```
+
+⚠️ The line below should be included when importing the package:
+
+```js
+import "vue-virtualised/dist/vue-virtualised.css";
 ```
 
 ## Usage

src/components/VirtualisedTree.vue

@@ -33,14 +33,11 @@
 
 <script>
 import { defineComponent, defineAsyncComponent, ref, watch } from "vue";
+import VirtualisedBaseTree from "./Base/VirtualisedBaseTree.vue";
 
 export default defineComponent({
   name: "VirtualisedTree",
-  components: {
-    VirtualisedBaseTree: defineAsyncComponent(() =>
-      import("./Base/VirtualisedBaseTree.vue")
-    ),
-  },
+  components: { VirtualisedBaseTree },
   props: {
     nodes: {
       type: Array,