Merge in "What's cooking" history

The one-file-per-issue format is not an optimal way to maintain these documents in a self-respecting version control system. Granted, they do not "diff" very well, but that is something we can improve by defining a custom diff driver for them. "What's in" are just a glorified "git shortlog --no-merged" without any additional comments, and I am very tempted to drop them. I haven't issued them for quite some time, and nobody seems to have noticed.