docs: add StackBlitz online example (#658)

Author: 9aoy

website/docs/en/guide/start/quick-start.mdx

@@ -1,5 +1,11 @@
 # Quick start
 
+## Online examples
+
+You can try Rstest online without any setup by using the following examples:
+
+- [StackBlitz Example](https://stackblitz.com/~/github.com/rspack-contrib/rstest-stackblitz-example)
+
 ## Setup environment
 
 Before getting started, you will need to install [Node.js](https://nodejs.org/) >= 18, it is recommended to use the Node.js LTS version.

website/docs/zh/guide/start/quick-start.mdx

@@ -1,5 +1,11 @@
 # 快速上手
 
+## 在线示例
+
+你可以通过以下示例在线尝试 Rstest，无需任何设置：
+
+- [StackBlitz 示例](https://stackblitz.com/~/github.com/rspack-contrib/rstest-stackblitz-example)
+
 ## 环境准备
 
 开始之前，需要先安装 [Node.js](https://nodejs.org/) >= 18 版本，推荐使用 Node.js LTS 版本。