Update README.md

Author: SaraTorrey

README.md

@@ -48,7 +48,7 @@ Are you having trouble using the extension?
 We'd like to help you out the best we can!
 There are a couple of things to consider when you're traversing anything Axon:
 
-* Checking the [reference guide](https://docs.axoniq.io/reference-guide/extensions/) should be your first stop,
+* Checking the [reference guide](https://docs.axoniq.io/reference-guide/extensions/kotlin) should be your first stop,
  as the majority of possible scenarios you might encounter when using Axon should be covered there.
 * If the Reference Guide does not cover a specific topic you would've expected,
  we'd appreciate if you could file an [issue](https://github.com/AxonIQ/reference-guide/issues) about it for us.