doc: minor updates to onboarding doc

PR-URL: https://github.com/nodejs/node/pull/8060
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/onboarding.md

@@ -1,14 +1,12 @@
-## pre-setup
+# Onboarding
 
-Ensure everyone is added to https://github.com/orgs/nodejs/teams/collaborators
+This document is an outline of the things we tell new Collaborators at their
+onboarding session.
 
+* Prior to the onboarding session, add the new Collaborators to
+[the Collaborators team](https://github.com/orgs/nodejs/teams/collaborators).
 
-## onboarding to nodejs
-
-### intros
-
-
-### **thank you** for doing this
+## **thank you** for doing this
 
   * going to cover four things:
     * local setup
@@ -16,8 +14,7 @@ Ensure everyone is added to https://github.com/orgs/nodejs/teams/collaborators
     * issues, labels, and reviewing code
     * merging code
 
-
-### setup:
+## setup
 
   * notifications setup
     * use https://github.com/notifications or set up email
@@ -34,7 +31,7 @@ Ensure everyone is added to https://github.com/orgs/nodejs/teams/collaborators
   * `#node-dev` on `chat.freenode.net` is the best place to interact with the CTC / other collaborators
 
 
-### a little deeper about the project
+## a little deeper about the project
 
   * collaborators are effectively part owners
     * the project has the goals of its contributors
@@ -46,7 +43,7 @@ Ensure everyone is added to https://github.com/orgs/nodejs/teams/collaborators
     * generally: try to be nice to people
 
 
-### managing the issue tracker
+## managing the issue tracker
 
   * you have (mostly) free rein – don't hesitate to close an issue if you are confident that it should be closed
     * this will come more naturally over time
@@ -113,7 +110,7 @@ Ensure everyone is added to https://github.com/orgs/nodejs/teams/collaborators
       * The remaining elements on the form are typically unchanged with the exception of `POST_STATUS_TO_PR`. Check that if you want a CI status indicator to be automatically inserted into the PR.
 
 
-### process for getting code in:
+## process for getting code in
 
   * the collaborator guide is a great resource: https://github.com/nodejs/node/blob/master/COLLABORATOR_GUIDE.md#technical-howto
 
@@ -145,7 +142,7 @@ Ensure everyone is added to https://github.com/orgs/nodejs/teams/collaborators
     * Info on PRs that don't like to apply found under [**"If `git am` fails"**](./onboarding-extras.md#if-git-am-fails).
 
 
-### Landing PRs
+## Landing PRs
 
 * Please never use GitHub's green "Merge Pull Request" button.
   * If you do, please force-push removing the merge.
@@ -174,7 +171,7 @@ Landing a PR
     * close the original PR with "Landed in `<commit hash>`".
 
 
-### exercise: make PRs adding yourselves to the README.
+## exercise: make PRs adding yourselves to the README
 
   * Example: https://github.com/nodejs/node/commit/7b09aade8468e1c930f36b9c81e6ac2ed5bc8732
     * to see full URL: `git log 7b09aade8468e1c930f36b9c81e6ac2ed5bc8732 -1`
@@ -184,7 +181,7 @@ Landing a PR
   * Make sure to added the `PR-URL: <full-pr-url>`!
 
 
-### final notes:
+## final notes
 
   * don't worry about making mistakes: everybody makes them, there's a lot to internalize and that takes time (and we recognize that!)
   * very few (no?) mistakes are unrecoverable