`Not_Assigned` category?

I’ve submitted this through http://www.unicode.org/reporting.html, but track it here since it affects this repository.

Both http://www.unicode.org/reports/tr18/#Categories as the latest draft of that document i.e. http://www.unicode.org/reports/tr18/proposed.html#Categories list the following example:

\p{General_Category = Not_Assigned}

However, Not_Assigned is not a valid General_Category name as per the table here: http://unicode.org/reports/tr44/#GC_Values_Table

Suggested fix: use Unassigned instead in the example.

\p{General_Category = Unassigned}

It would be easy enough to add a Not_Assigned alias but I’d rather not if this is indeed a mistake.

比較 Unicode TR18 中的 General_Category 範例與 TR44 General_Category Values Table 中的有效名稱，並以連結的章節作為起點。完成的標準是該範例始終使用有效的類別名稱，或 Unicode 報告確認不需要變更 repository。