Fix misspellings

kittens/icat/transmit.go

@@ -144,7 +144,7 @@ func transmit_file(imgd *image_data, frame_num int, frame *image_frame) (err err
 		if err != nil {
 			return fmt.Errorf("Failed to convert image data output file: %s to absolute path with error: %w", frame.filename, err)
 		}
-		frame.filename = "" // so it isnt deleted in cleanup
+		frame.filename = "" // so it isn't deleted in cleanup
 	} else {
 		is_temp = true
 		if frame.shm != nil && frame.shm.FileSystemName() != "" {