Document that rejectRequestWith requires closing the stream

I just ran into the same issue described in [jaspervdj#211](jaspervdj#211). In my case I had noticed the note about calling `Stream.close` in the `rejectRequest` docs but I didn't realize that the disclaimer applied to `rejectRequestWith` as well. Based on [this comment](jaspervdj#211 (comment)) maybe it makes sense to close the underlying stream when rejecting the request, but short of that maybe this note will help someone else avoid the same issue.

Author: ceedubs

src/Network/WebSockets/Connection.hs

@@ -227,6 +227,7 @@ defaultRejectRequest = RejectRequest
 
 
 --------------------------------------------------------------------------------
+-- | Requires calling 'pendingStream' and 'Stream.close'.
 rejectRequestWith
     :: PendingConnection  -- ^ Connection to reject
     -> RejectRequest      -- ^ Params on how to reject the request