doc: fix code examples in stream.md

* Replace `console.error()` with `console.log()`.
* Fix case and punctuation in logged output.

PR-URL: https://github.com/nodejs/node/pull/24112


Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>