build: Shorten Travis CI notification to 1 line

Override the default and instead just emit one line.
Also move it to #mediawiki-i18n.

.travis.yml

@@ -11,4 +11,6 @@ script:
 notifications:
   irc:
     channels:
-      - "chat.freenode.net##krinkle"
+      - "chat.freenode.net#mediawiki-i18n"
+    template:
+      - "%{repository}#%{build_number} (%{branch} - %{commit}: %{author}) %{message} - %{build_url}"