internal/golangorgx/gopls: Use the correct error.

This was found using the author's https://github.com/alingse/nilnesserr
tool. Although this is vendored code, I think this code is something we
might make use of, and so it's worthwhile having this fix.

Closes #3863 as merged as of commit a45c605.

Signed-off-by: alingse <[email protected]>
Change-Id: Id31a252ce9807877eed34a6947ca51894469f1c5
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1213489
Unity-Result: CUE porcuepine <[email protected]>
Reviewed-by: Daniel Martí <[email protected]>
TryBot-Result: CUEcueckoo <[email protected]>
Reviewed-by: Matthew Sackman <[email protected]>

Author: alingse

Diff for: internal/golangorgx/gopls/lsprpc/lsprpc.go

@@ -392,7 +392,7 @@ func (f *forwarder) replyWithDebugAddress(outerCtx context.Context, r jsonrpc2.R
 		addr, err = di.Serve(outerCtx, addr)
 		if err != nil {
 			event.Error(outerCtx, "starting debug server", err)
-			return r(ctx, result, outerErr)
+			return r(ctx, result, err)
 		}
 		urls := []string{"http://" + addr}
 		modified.URLs = append(urls, modified.URLs...)