chore: update vue3 playground test code

vue3-playground/App.vue

@@ -1,18 +1,21 @@
 <script lang="ts" setup>
 import { version } from 'vue-demi'
 import { reactive } from 'vue'
+import c from 'highlight.js/lib/languages/c'
+import { CodeDiff, hljs } from '../src/index'
 
+hljs.registerLanguage('c', c)
 // import { oldLongText } from '../demo/text/old-long-text'
 // import { newLongText } from '../demo/text/new-long-text'
 
 const form = reactive({
   // oldString: oldLongText,
   // newString: newLongText,
-  oldString: '{\n  "code": "200",\n  "msg": "请求成功",\n  "data": {\n    "hitokoto": "往者不可谏，来者犹可追。",\n    "from": "论语·微子篇"\n  },\n  "time": "2024-01-12 17:27:03"\n}',
-  newString: '{\n  "code": "200",\n  "msg": "请求成功",\n  "data": {\n    "hitokoto": "成熟的人眼里满是前途，稚嫩的人眼里满是爱恨情仇。",\n    "from": "网易云热评"\n  },\n  "time": "2024-01-12 17:27:06"\n}',
+  oldString: '#include <stdio.h>',
+  newString: '123\n123',
   filename: 'oldFile',
   newFilename: 'newFile',
-  language: 'json',
+  language: 'c',
   diffStyle: 'word',
   outputFormat: 'side-by-side',
   ignoreMatchingLines: 'time',

vue3-playground/main.ts

@@ -1,7 +1,5 @@
 import { createApp } from 'vue'
-import TemplateComponent from '../src/index'
 import App from './App.vue'
 
 const app = createApp(App)
-app.use(TemplateComponent)
 app.mount('#app')