Better describe the listbanned rpc call

Author: Elias Rohrer

reference/rpc/listbanned.rst

@@ -8,6 +8,18 @@ listbanned
 
 List all banned IPs/Subnets.
 
+Result
+~~~~~~
+::
+
+  [
+    {
+    "address": <address>,             (string) The banned address.
+    "banned_until": <time>,           (numeric) The time (in seconds since Jan 1 1970 GMT) until the address is banned.
+    "ban_created": <time>,            (numeric) The time (in seconds since Jan 1 1970 GMT) when the ban was created.
+    }
+  ]
+
 Examples
 ~~~~~~~~