fix(AIP-143): align CLDR country/region guidance with CLDR list (#1447)

Author: noahdietz

aip/general/0143.md

@@ -90,6 +90,7 @@ format][] to represent this, and the field **must** be named `utc_offset`.
 
 ## Changelog
 
+- **2024-11-12**: Change country/region code list to CLDR list from IANA list
 - **2020-05-12**: Replaced `country_code` guidance with `region_code`,
   correcting an original error.
 
@@ -101,6 +102,6 @@ format][] to represent this, and the field **must** be named `utc_offset`.
 [iso]: https://www.iso.org/
 [iso-4217]: https://en.wikipedia.org/wiki/ISO_4217
 [iso-8601 format]: https://en.wikipedia.org/wiki/ISO_8601#Time_offsets_from_UTC
-[list]: https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry
+[list]: https://www.unicode.org/cldr/charts/46/supplemental/territory_information.html
 [money]: https://github.com/googleapis/googleapis/blob/master/google/type/money.proto
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