Remove unused channels

Author: GuillaumeGomez

docs-src/contact.md

@@ -8,14 +8,7 @@ There are multiple ways to contact directly `Gtk-rs` developers:
 
 # IRC
 
-In here you have the choice between two channels on two different servers:
-
- * #gtk-rs on irc.mozilla.org
- * #rust on irc.gimp.org
-
-# Gitter
-
-You can find us on gitter at this address: [gitter.im/gtk-rs/gtk](https://gitter.im/gtk-rs/gtk).
+#rust on irc.gimp.org
 
 # Github