RowColumnScanning tutorial omits resistors [MKC-555]

[matthijskooijman]

The tutorial at https://www.arduino.cc/en/Tutorial/RowColumnScanning omits resistors in driving the LEDs. There is a common misconception in the Arduino scene, that I/O pins are somehow (safely) current limited and need no resistors with LEDs, but this is not actually the case. It would be good if at least official Arduino documentation set the right example...

[clumsymon]

The flawed tutorial is still online after 2 years and still harming the hardware of Arduino users. If this tutorial is not going to be fixed it should be removed completely.