doc: update irc channels: #node.js and #node-dev

IRC (general questions): irc.freenode.net #node.js
IRC (node core development): irc.freenode.net #node-dev

PR-URL: https://github.com/nodejs/node/pull/2743
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>

CONTRIBUTING.md

@@ -65,9 +65,11 @@ projects. Do not send your patch to us, we cannot accept it.
 In case of doubt, open an issue in the
 [issue tracker](https://github.com/nodejs/node/issues/) or contact one of the
 [project Collaborators](https://github.com/nodejs/node/#current-project-team-members).
-([IRC](http://webchat.freenode.net/?channels=io.js) is often the best medium.) Especially do so if you plan to work on something big. Nothing is more
+Especially do so if you plan to work on something big. Nothing is more
 frustrating than seeing your hard work go to waste because your vision
-does not align with the project team.
+does not align with the project team. Node.js has two IRC channels,
+[#Node.js](http://webchat.freenode.net/?channels=node.js) for general help and questions, and
+[#Node-dev](http://webchat.freenode.net/?channels=node-dev) for development of node core specifically.
 
 
 ### Step 2: Branch

README.md

@@ -349,8 +349,8 @@ Instructions:
 * [CODE_OF_CONDUCT.md](./CODE_OF_CONDUCT.md)
 * [CONTRIBUTING.md](./CONTRIBUTING.md)
 * [GOVERNANCE.md](./GOVERNANCE.md)
-* IRC:
-  [#io.js on Freenode.net](http://webchat.freenode.net?channels=io.js&uio=d4)
+* IRC (general questions): [#node.js on Freenode.net](http://webchat.freenode.net?channels=node.js&uio=d4)
+* IRC (node core development): [#node-dev on Freenode.net](http://webchat.freenode.net?channels=node-dev&uio=d4)
 * [nodejs/node on Gitter](https://gitter.im/nodejs/node)
 
 ## Security

doc/node.1

@@ -831,4 +831,6 @@ See the website for documentation https://nodejs.org/
 
 Mailing list: http://groups.google.com/group/nodejs
 
-IRC: irc.freenode.net #io.js
+IRC (general questions): irc.freenode.net #node.js
+
+IRC (node core development): irc.freenode.net #node-dev