IRC channel

Document which IRC channel should be used for libdisplay-info. We've been using #dri-devel or #wayland so far. Decide which channel is preferred:

• Are the communities in either #dri-devel or #wayland okay with this project using these channels?
• Should we pick another one? (e.g. #emersion is a catch-all for my projects, but if we want to move the lib out of my namespace may not be a good choice.)
• Should we establish a new channel? (May be a bit premature/too much, since the project is quite young and small.)