Workers KV example

Their is an example in the readme for getting a value from a workers KV kew, but it is not clear on how the response is used. Can the example either be documented on what it is doing, or can a functional example be added that can be easily tested? I will gladly add clarification if needed.

先阅读 README 中的 Workers KV 示例，并确定其响应预期如何使用。明确说明这种用法，或添加一个可测试的功能性示例；当 README 让响应处理易于理解并提供一个可验证的示例时，即视为完成。

由索引模型根据 Issue 内容生成。