Merge pull request #1303 from nats-io/fix_doc_link

[FIXED] Documentation link [ci skip]

Author: derekcollison

README.md

@@ -10,7 +10,7 @@ The NATS Streaming Server is being deprecated.  Critical bug fixes and security
 
 ## Documentation
 
-* [Official documentation](https://docs.nats.io/legacy/stan)
+* [Official documentation](https://nats-io.gitbook.io/legacy-nats-docs/nats-streaming-server-aka-stan)
 
 ## Clients