[Announcements] Make every part of an announcement clickable.

[JamesKCOS]

It’s been confusing for my students (and for me at times) that you have to click the title of an announcement and not any part of the preview. I have had students who were using the “reply” option as a workaround. Just the fact that the title looks like regular black text breaks internet design language. It needs to be underlined at the very least if not a different color as well.