doc: remove subsystem from pull request template

Remove request that user provide a list of subsystems in the pull request template. * We already ask them to put the subsystems in the first line of the commit message. * The subsystem is usually easy to determine. * We have a bot that applies subsystem labels on new PRs and it seems to do a rather good job. Tools over rules. Let the bot do it. * The fewer unnecessary things we ask for in the template, the lower the barrier to entry. * Anecdotal, but I have never found it useful to have the person submitting the PR list out subsystems in the pull request post. Backport-PR-URL: #22380 PR-URL: #19125 Reviewed-By: Luigi Pinca <[email protected]> Reviewed-By: Michaël Zasso <[email protected]> Reviewed-By: Anatoli Papirovski <[email protected]> Reviewed-By: Tobias Nießen <[email protected]> Reviewed-By: Benjamin Gruenbaum <[email protected]> Reviewed-By: Сковорода Никита Андреевич <[email protected]> Reviewed-By: Gibson Fahnestock <[email protected]> Reviewed-By: Gus Caplan <[email protected]> Reviewed-By: Ruben Bridgewater <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: Matheus Marchini <[email protected]> Reviewed-By: Tiancheng "Timothy" Gu <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Jon Moss <[email protected]> Reviewed-By: Kyle Farnung <[email protected]>

Author: Trott

.github/PULL_REQUEST_TEMPLATE.md

@@ -14,6 +14,3 @@ Contributors guide: https://github.com/nodejs/node/blob/master/CONTRIBUTING.md
 -[ ] tests and/or benchmarks are included
 -[ ] documentation is changed or added
 -[ ] commit message follows [commit guidelines](https://github.com/nodejs/node/blob/master/doc/guides/contributing/pull-requests.md#commit-message-guidelines)
-
-##### Affected core subsystem(s)
-<!-- Provide affected core subsystem(s) (like doc, cluster, crypto, etc). -->