fix typo in JSON

nips/11.md

@@ -19,7 +19,7 @@ When a relay receives an HTTP(s) request with an `Accept` header of `application
   supported_nips: <a list of NIP numbers supported by the relay>,
   software: <string identifying relay software URL>,
   version: <string version identifier>
-}]
+}
 ```
 
 Any field may be omitted, and clients MUST ignore any additional fields they do not understand.