docs(readme): improve api reference (#128)

Author: stainless-bot

README.md

@@ -8,7 +8,7 @@ and offers both synchronous and asynchronous clients powered by [httpx](https://
 
 ## Documentation
 
-The API documentation can be found [here](https://docs.withorb.com/reference/api-reference).
+The REST API documentation can be found [on docs.withorb.com](https://docs.withorb.com/reference/api-reference). The full API of this library can be found in [api.md](https://www.github.com/orbcorp/orb-python/blob/main/api.md).
 
 ## Installation