internal/lsp: don't log context.Cancelation in diagnostics

Fixes #34103.

Change-Id: I76e713d54422d31b587cedd0e4359c8b3bc7845e
Reviewed-on: https://go-review.googlesource.com/c/tools/+/215019
Run-TryBot: Rebecca Stambler <[email protected]>
TryBot-Result: Gobot Gobot <[email protected]>
Reviewed-by: Heschi Kreinick <[email protected]>

Author: stamblerre

internal/lsp/diagnostics.go

@@ -39,6 +39,9 @@ func (s *Server) diagnose(ctx context.Context, snapshot source.Snapshot) {
 	// Diagnose all of the packages in the workspace.
 	go func() {
 		wsPackages, err := snapshot.WorkspacePackages(ctx)
+		if ctx.Err() != nil {
+			return
+		}
 		if err != nil {
 			log.Error(ctx, "diagnose: no workspace packages", err, telemetry.Directory.Of(snapshot.View().Folder))
 			return