av1an: Show amount of finished chunks in temp folder deletion message

Author: n00mkrad

ff-utils-winforms/UI/Tasks/Av1anUi.cs

@@ -337,7 +337,9 @@ public static void AskDeleteTempFolder (string dir)
                 return;
             }
 
-            DialogResult dialog = MessageBox.Show($"Av1an has finished.\nDo you want to delete the temporary folder ({FormatUtils.Bytes(dirSize)}) of this encode?", "Delete av1an temp folder?", MessageBoxButtons.YesNo, MessageBoxIcon.Warning, MessageBoxDefaultButton.Button1, MessageBoxOptions.DefaultDesktopOnly);
+            string size = FormatUtils.Bytes(dirSize);
+            string chunks = $"{IoUtils.GetFileInfosSorted(Path.Combine(dir, "encode"), false, "*.*").Where(x => x.Length >= 1024).Count()} encoded video chunks";
+            DialogResult dialog = MessageBox.Show($"Av1an has finished.\nDo you want to delete the temporary folder of this encode? It's {size} and contains {chunks}.", "Delete av1an temp folder?", MessageBoxButtons.YesNo, MessageBoxIcon.Warning, MessageBoxDefaultButton.Button1, MessageBoxOptions.ServiceNotification);
 
             if (dialog == DialogResult.Yes)
                 IoUtils.TryDeleteIfExists(dir);