Re: [tz] Yukon, NWT, and Nunavut (Canada)

Thanks for all that careful work. I installed the attached patches, which implement the changes you suggested, except that they retain 2022f's guess that Yukon's 1965-04-22 spring forward was 00:00→02:00 instead of 02:00→04:00 as the former seems a bit more likely to me (admittedly this is just a guess either way). Also, I looked for other evidence about Pangnirtung and found a Google Books snippet suggesting that EST was used in 1959, so these patches move America/Pangnirtung's data to 'backzone' since it appears there's no difference from America/Iqaluit since 1970. There is a backward-compatibility link as usual.