LibUnicode: Parse and generate standard decimal formatting rules

Author: https://github.com/trflynn89
Commit: bffd73e0d4
Pull-request: https://github.com/SerenityOS/serenity/pull/10873
Reviewed-by: https://github.com/linusg

Userland/Libraries/LibUnicode/Locale.h

@@ -79,6 +79,7 @@ struct LocaleID {
 };
 
 enum class StandardNumberFormatType : u8 {
+    Decimal,
     Percent,
 };