Adds lines between the points of the same category in scatter.R plots. PR-URL: https://github.com/nodejs/node/pull/22074 Reviewed-By: Andreas Madsen <amwebdk@gmail.com> Reviewed-By: Anatoli Papirovski <apapirovski@mac.com> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>