process: fix typo in comments

Fixing a typo in comments, the word 'remaining' had a typo.

PR-URL: https://github.com/nodejs/node/pull/11503
Fixes: https://github.com/nodejs/node/issues/11491


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Yuta Hiroto <hello@about-hiroppy.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>