feat: gracefully handle additional plural data in CLDR

Author: nijel

scripts/export-cldr.py

@@ -246,6 +246,9 @@ class LanguageDict(TypedDict, total=False):
     data = json.load(handle)
     for cldr_code, categories in data["supplemental"]["plurals-type-cardinal"].items():
         code = map_code(cldr_code)
+        # Copy language data from basic
+        if code not in LANGUAGES and "_" in code:
+            LANGUAGES[code] = LANGUAGES[code.split("_", 1)[0]]
         if len(categories) == 1:
             # Just one category
             LANGUAGES[code]["plurals"] = 1