[Realtime] Fix simulcast example dead link (#22860)

Author: palashgo

src/content/docs/realtime/simulcast.mdx

@@ -83,4 +83,4 @@ Here's an example of how to use simulcast with Cloudflare Realtime:
 2. Use the [Cloudflare Realtime API](/realtime/https-api) to push this local track, by calling the /tracks/new endpoint.
 3. Use the [Cloudflare Realtime API](/realtime/https-api) to start pulling a remote track (from another browser or device), by calling the /tracks/new endpoint and specifying the `simulcast` configuration object along with the remote track ID you get from step 2.
 
-For more examples, check out the [Realtime Examples GitHub repository](https://github.com/cloudflare/calls-examples/tree/main/simulcast).
+For more examples, check out the [Realtime Examples GitHub repository](https://github.com/cloudflare/calls-examples/tree/main/echo-simulcast).