Documents: fix WinziPrint args

Elwig/Helpers/TempFile.cs

@@ -5,6 +5,7 @@ namespace Elwig.Helpers {
     public sealed class TempFile : IDisposable {
         private int Usages = 0;
         public string FilePath { get; private set; }
+        public string FileName => Path.GetFileName(FilePath);
 
         public TempFile() : this(null) { }