Fix check for duplicated Windows time-zone IDs

A missing update of a "last" variable meant the loop inevitably did
nothing useful. Include type-annotation for last, while doing this.
Thankfully the check still doesn't find any duplications, now that
I've fixed it so that actually would, were any present.

Pick-to: 6.8 6.5
Change-Id: I672e6570359a3ff102a364d8af98c5c8c0bdc4d9
Reviewed-by: Mate Barany <mate.barany@qt.io>

util/locale_database/cldr.py

@@ -121,11 +121,12 @@ class CldrReader (object):
                 'They could be removed at the next major version.\n')
 
         # Check for duplicate entries in winIds:
-        last = ('', '', '')
+        last: tuple[str, str, str] = ('', '', '')
         winDup = {}
         for triple in sorted(winIds):
             if triple[:2] == last[:2]:
                 winDup.setdefault(triple[:2], []).append(triple[-1])
+            last = triple
         if winDup:
             joined = '\n\t'.join(f'{t}, {w}: ", ".join(ids)'
                                  for (w, t), ids in winDup.items())