Merge pull request #417 from PHPCSStandards/feature/contributing-add-note-about-cc-list

CONTRIBUTING: add table of contents + note about cc list

Author: jrfnl

.github/CONTRIBUTING.md

@@ -4,6 +4,25 @@ Contributing
 Thank you for your interest in contributing to PHP_CodeSniffer!
 
 
+## Table of Contents
+
+* [Reporting Bugs](#reporting-bugs)
+   - [Reporting Security Issues](#reporting-security-issues)
+   - [Support/Questions About Using PHP_CodeSniffer](#supportquestions-about-using-php_codesniffer)
+* [Contributing Without Writing Code](#contributing-without-writing-code)
+   - [Bug Triage](#bug-triage)
+   - [Testing Open Pull Requests](#testing-open-pull-requests)
+   - [Writing sniff documentation](#writing-sniff-documentation)
+   - [Other tasks](#other-tasks)
+* [Contributing With Code](#contributing-with-code)
+   - [Requesting/Submitting New Features](#requestingsubmitting-new-features)
+   - [Getting started](#getting-started)
+   - [While working on a patch](#while-working-on-a-patch)
+   - [Writing tests](#writing-tests)
+   - [Submitting your pull request](#submitting-your-pull-request)
+* [Licensing](#licensing)
+
+
 ## Reporting Bugs
 
 Please search the [open issues](https://github.com/PHPCSStandards/PHP_CodeSniffer/issues) to see if your issue has been reported
@@ -149,6 +168,17 @@ This is an open invitation for interested parties to gather their thoughts about
 > Kind request: If you don't have something to add to the discussion, but do want to indicate a positive or negative opinion
 > on a topic, please add an emoji on the original post instead of leaving a comment.
 
+> :bulb: On a subset of these issues - the ones which impact maintainers or integrators -, a list of known interested parties
+> will be pinged (cc-ed) to gather their thoughts on the topic.
+>
+> This list is public and
+> [maintained in a markdown file](https://github.com/PHPCSStandards/PHP_CodeSniffer/blob/master/.github/community-cc-list.md).
+>
+> To add or remove yourself to/from this list, submit a PR to the repo updating the `community-cc-list.md` file.
+> PRs adding/removing _other people_ to/from the list will only be merged if the people being added/removed leave a comment
+> on the PR consenting to it.
+
+
 #### Issues marked with "Status: needs investigation"
 
 Sometimes an issue has been identified, but it has not yet been pinpointed what the exact cause of the problem is.