[contributing] change irc channel to a link

CONTRIBUTING.md

@@ -13,7 +13,7 @@ At any given time the Kibana team at Elastic is working on dozens of features an
 Let's just get this out there: **Feel free to +1 an issue**. That said, a +1 isn't a vote. We keep up on highly commented issues, but comments are but one of many reasons we might, or might not, work on an issue. A solid write up of your use case is more likely to make your case than a comment that says *+10000*.
 
 #### My issue isn't getting enough attention
-First of all, sorry about that, we want you to have a great time with Kibana! You should join us on IRC (#kibana on freenode) and chat about it. Github is terrible for conversations. With that out of the way, there are a number of variables that go into deciding what to work on. These include priority, impact, difficulty, applicability to use cases, and last, and importantly: What we feel like working on.
+First of all, sorry about that, we want you to have a great time with Kibana! You should join us on IRC ([#kibana](https://kiwiirc.com/client/irc.freenode.net/?#kibana) on freenode) and chat about it. Github is terrible for conversations. With that out of the way, there are a number of variables that go into deciding what to work on. These include priority, impact, difficulty, applicability to use cases, and last, and importantly: What we feel like working on.
 
 ### I want to help!
 **Now we're talking**. If you have a bugfix or new feature that you would like to contribute to Kibana, please **find or open an issue about it before you start working on it.** Talk about what you would like to do. It may be that somebody is already working on it, or that there are particular issues that you should know about before implementing the change.