Bug squad: remember the regtest comparison

[Graham Percival]

One of your vital tasks -- arguably even more important than
replying to emails -- is to check the regtest comparison for every
release.

If you've read anything that looks relevant and was linked to
directly from the CG chapter on Issues, and don't know how to do
this, then clearly we need to talk about how to improve the CG in
this regard.

Cheers,
- Graham