Updated the 'Announcement' section of the release checklist document.
This now includes details about initially composing the message using the relax wiki
(http://wiki.nmr-relax.com), and then how that text and the CHANGES file are used for the email
announcement (http://news.gmane.org/gmane.science.nmr.relax.announce) and the Gna! news item
(https://gna.org/news/?group=relax).
