Please use either "sourceware.org" or (when possible) "cygwin.com" in announcement messages

[Christopher Faylor]

I think many people have copied an old announcement of mine for their
cygwin-announce messages which includes a "http://sources.redhat.com/..." URL.
That name is now deprecated.  Please change this URL to point to either
sourceware.org or cygwin.com as appropriate.

The reason for this is that we're halfheartedly considering moving
sourceware.org to another provider entirely so using sources.redhat.com
will be problematic.  Probably nothing will come of this but it really
does make sense to change the URL regardless.

And, no, I'm not going to automatically add the unsubscribe message to
everything that shows up for cygwin-announce.  But thanks for asking.

cgf