Fix Dead Links in @neshca/cache-handler-redis example README.md (#67415)

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### What?
Updating links to the @neshca/cache-handler documentation that are dead.
### Why?
To improve developer experience (DX) by ensuring README.md links are
functional.
### How?
Edit the Markdown links in the README.md file of the example to point to
the correct URLs.


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Hello,

This PR updates dead links in the @neshca/cache-handler-redis example's
README.md to ensure they point to the correct URLs.

Thank you for your review!

Co-authored-by: Jiwon Choi <devjiwonchoi@gmail.com>

examples/cache-handler-redis/README.md

@@ -35,9 +35,9 @@ For detailed information on configuration and usage, please refer to our compreh
 
 ## Key Features and Considerations
 
-- **Handlers:** The `@neshca/cache-handler` package includes [Handlers](https://caching-tools.github.io/next-shared-cache/redis-stack) for seamless integration with Redis.
+- **Handlers:** The `@neshca/cache-handler` package includes [Handlers](https://caching-tools.github.io/next-shared-cache/handlers/redis-stack) for seamless integration with Redis.
 
-- **Create Your Own Handlers:** Take a look at [Custom Redis Handler](https://caching-tools.github.io/next-shared-cache/redis-stack-custom) and use it as a basis to create your own handler.
+- **Create Your Own Handlers:** Take a look at [Custom Redis Handler](https://caching-tools.github.io/next-shared-cache/usage/creating-a-custom-handler) and use it as a basis to create your own handler.
 
 - **Redis Server Setup:** Ensure your Redis server is running and properly configured before starting your Next.js application.