doc: specify fast-tracking

Currently the documentation is not specific how fast-tracking should
be applied. This specifies exactly how things should be done to prevent
confusion.

PR-URL: https://github.com/nodejs/node/pull/22929


Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: John-David Dalton <john.david.dalton@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Weijia Wang <starkwang@126.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Matheus Marchini <mat@mmarchini.me>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: Yuta Hiroto <hello@hiroppy.me>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: George Adams <george.adams@uk.ibm.com>