doc: make docs more welcoming and descriptive for newcomers

Fixes: nodejs#26287
PR-URL: nodejs#38056
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

CONTRIBUTING.md

@@ -1,5 +1,21 @@
 # Contributing to Node.js
 
+Contributions to Node.js include code, documentation, answering user questions,
+running the project's infrastructure, and advocating for all types of Node.js
+users.
+
+The Node.js project welcomes all contributions from anyone willing to work in
+good faith with other contributors and the community. No contribution is too
+small and all contributions are valued.
+
+The Node.js project has an open governance model.
+Individuals making significant and valuable contributions are made
+Collaborators and given commit-access to the project. See the
+[GOVERNANCE.md](./GOVERNANCE.md) document for more information about how this
+works.
+
+## Contents
+
 * [Code of Conduct](#code-of-conduct)
 * [Issues](#issues)
 * [Pull Requests](#pull-requests)
@@ -22,6 +38,9 @@ See [details on our policy on Code of Conduct](./doc/contributing/code-of-conduc
 
 ## [Pull Requests](./doc/contributing/pull-requests.md)
 
+Pull Requests are the way concrete changes are made to the code, documentation,
+dependencies, and tools contained in the `nodejs/node` repository.
+
 * [Dependencies](./doc/contributing/pull-requests.md#dependencies)
 * [Setting up your local environment](./doc/contributing/pull-requests.md#setting-up-your-local-environment)
 * [The Process of Making Changes](./doc/contributing/pull-requests.md#the-process-of-making-changes)

GOVERNANCE.md

@@ -8,6 +8,9 @@
 * [Technical steering committee](#technical-steering-committee)
   * [TSC meetings](#tsc-meetings)
 * [Collaborator nominations](#collaborator-nominations)
+  * [Who can nominate Collaborators?](#who-can-nominate-collaborators)
+  * [Ideal Nominees](#ideal-nominees)
+  * [Nominating a new Collaborator](#nominating-a-new-collaborator)
   * [Onboarding](#onboarding)
 * [Consensus seeking process](#consensus-seeking-process)
 
@@ -124,11 +127,26 @@ the issue tracker is:
 
 ## Collaborator nominations
 
-Existing collaborators can nominate someone to become a collaborator. Nominees
-should have significant and valuable contributions across the Node.js
+### Who can nominate Collaborators?
+
+Existing Collaborators can nominate someone to become a Collaborator.
+
+### Ideal Nominees
+
+Nominees should have significant and valuable contributions across the Node.js
 organization.
 
-To nominate a new collaborator, open an issue in the [nodejs/node][] repository.
+Contributions can be:
+
+* Opening pull requests.
+* Comments and reviews.
+* Opening new issues.
+* Participation in other projects, teams, and working groups of the Node.js
+  organization.
+
+### Nominating a new Collaborator
+
+To nominate a new Collaborator, open an issue in the [nodejs/node][] repository.
 Provide a summary of the nominee's contributions. For example:
 
 * Commits in the [nodejs/node][] repository.