[Exim] NewStuff/spec.txt comments

So I'm looking at upgrading from 4.14 to 4.22 (on my production servers,
my home machine is a day-of-release upgrade =)), and I notice a
peculiarity with the docs. It's hard to see documentation changes for
documentation-updating releases. That is, I read NewStuff faithfully up
through 4.14, then I went to read the changes for 4.20, 4.21, and 4.22 and
found that 4.20 is difficult to get an easy view of new options.

I know ChangeLog contains some notes that would probably allow me to track
down all of the changes in spec.txt, but not easily. Maybe at the
documentation-updating releases it might be worth stating that the docs
are up-to-date and also including the changes for 4.20.

Or maybe I'm a whiner and should go on about my business =).

Thanks,
--John