all: remove repetitive words

Change-Id: Idad45a4c8352116b68eca172329214dbfb89b294
Reviewed-on: https://go-review.googlesource.com/c/tools/+/509696
Run-TryBot: shuang cui <imcusg@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>

internal/jsonrpc2/serve.go

@@ -104,7 +104,7 @@ func (s *Server) run(ctx context.Context) {
 		rwc, err := s.listener.Accept(ctx)
 		if err != nil {
 			// Only Shutdown closes the listener. If we get an error after Shutdown is
-			// called, assume that that was the cause and don't report the error;
+			// called, assume that was the cause and don't report the error;
 			// otherwise, report the error in case it is unexpected.
 			if atomic.LoadInt32(&s.closing) == 0 {
 				s.async.setError(err)