chore(docs): minor update to formatting of API link in README (#1550)

Author: stainless-app[bot]

README.md

@@ -8,7 +8,7 @@ and offers both synchronous and asynchronous clients powered by [httpx](https://
 
 ## Documentation
 
-The REST API documentation can be found [on platform.openai.com](https://platform.openai.com/docs). The full API of this library can be found in [api.md](api.md).
+The REST API documentation can be found on [platform.openai.com](https://platform.openai.com/docs). The full API of this library can be found in [api.md](api.md).
 
 ## Installation