doc: update stream.pipeline() signature

The  `...transforms` parameter is optional.

Refs: https://github.com/nodejs/node/blob/0875837417/lib/internal/streams/pipeline.js#L130-L132
Refs: https://github.com/nodejs/node/blob/e559842188/doc/api/stream.md#streams-compatibility-with-async-generators-and-async-iterators

PR-URL: https://github.com/nodejs/node/pull/31789


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Robert Nagy <ronagy@icloud.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>