[tz] Grouped country lists are confusing

[Stephen Colebourne]

Recent changes merged the comments acting as country headers. Thus, a
typical merged header is now:

# Denmark
# Germany
# Norway
# Sweden

It is very confusing to suggest that all four countries are evenly
represented here, as the commentary is typically all about the primary
country (Germany in this case). The alphabetical list is decidedly
unhelpful too, as nothing indicates which country the Zone's city
relates to.

Can I propose these comments be altered to something like:

# Germany
# also applicable since 1970 to Denmark
# also applicable since 1970 to Norway
# also applicable since 1970 to Sweden

thanks
Stephen