Prefer `{Date,Time}.current` over `.today`/`.now`

`Date.current` and `Time.current` take `Time.zone` and
`config.time_zone` into account, falling back to `Date.today` and
`Time.now` respectively if a zone isn't set.
> I agree it's diff-noise, and I'm willing to add it back if told to do so.

I think that's a good idea, though I wouldn't get so authoritarian as to *tell* you to :).

I'm open to a separate trailing-whitespace-in-prose discussion, though I'm not sure the best forum.