doc: edit onboarding guide to clarify when mailmap addition is needed

PR-URL: nodejs#55334
Reviewed-By: Michael Dawson <[email protected]>
Reviewed-By: Richard Lau <[email protected]>
Reviewed-By: Moshe Atlow <[email protected]>
Reviewed-By: Rafael Gonzaga <[email protected]>
Reviewed-By: Jake Yuesong Li <[email protected]>
Reviewed-By: Marco Ippolito <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>

Author: aduh95

onboarding.md

@@ -216,16 +216,14 @@ needs to be pointed out separately during the onboarding.
     `git show --format=%B 6669b3857f0f43ee0296eb7ac45086cd907b9e94`
 * Collaborators are in alphabetical order by GitHub username.
 * Optionally, include your personal pronouns.
-* The PR should include an addition to the
-  [mailmap](.mailmap) file if the email
-  being added to the collaborator list does not match the email used for
-  commits. Otherwise tooling will not see the collaborator as being active and
-  may suggest removing them. See
-  [gitmailmap](https://git-scm.com/docs/gitmailmap) for information on the
-  format of the mailmap file.
-* Add the `Fixes: <collaborator-nomination-issue-url>` to the commit message
+* Commit, including a `Fixes: <collaborator-nomination-issue-url>` trailer
   so that when the commit lands, the nomination issue url will be
   automatically closed.
+* Run `tools/find-inactive-collaborators.mjs`. If that command outputs your name,
+  amend the commit to include an addition to the [mailmap](.mailmap) file. See
+  [gitmailmap](https://git-scm.com/docs/gitmailmap) for information on the
+  format of the mailmap file.
+* Push the commit to your own fork.
 * Label your pull request with the `doc`, `notable-change`, and `fast-track`
   labels. The `fast-track` label should cause the Node.js GitHub bot to post a
   comment in the pull request asking collaborators to approve the pull request