doc: remove resolving-a-bug-report from contributing docs

This section isn't particularly useful in this context and contributes
to making the document longer and less effective. This is part of a
larger effort to make the contributing docs brief, informative, and
friendly.

Refs: https://github.com/nodejs/TSC/issues/864#issuecomment-628646560

PR-URL: https://github.com/nodejs/node/pull/36905


Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>