ushort and short not supported

```
class Options
{
[Option('p', "port", Required = false, HelpText = "port number")]
public int Port { get;set; }
}
```

If i change the type of Port to ushort or short I get an error when starting the program:

"ERROR(S):
Error setting value to option 'p, port': Check if Option or Value attribute values are set
properly for the given type."

Expected behavior:
1. clear error message that the type is not supported
2. support the types ushort and short

使用 C# Options 範例重現回報的錯誤，將 Port 分別改為 int、ushort 和 short。追蹤選項值的轉換和錯誤回報路徑；當 ushort 和 short 能夠正常運作，或收到明確的不支援類型訊息，且測試涵蓋這兩種情況時，即視為完成。

由索引模型根據 Issue 內容生成。