Documents/Pdf: Add /s to PdfToPrinter call

Elwig/Documents/Pdf.cs

@@ -59,6 +59,7 @@ namespace Elwig.Documents {
         public static async Task Print(string path, int copies = 1) {
             var p = new Process() { StartInfo = new() { FileName = PdfToPrinter } };
             p.StartInfo.ArgumentList.Add(path);
+            p.StartInfo.ArgumentList.Add("/s");
             p.StartInfo.ArgumentList.Add($"copies={copies}");
             p.Start();
             await p.WaitForExitAsync();