Fix MIDI note-on events being converted to note-off events

Update documentation with note about MIDI velocity interpretation

core/os/midi_driver.cpp

@@ -86,11 +86,6 @@ void MIDIDriver::receive_input_packet(uint64_t timestamp, uint8_t *data, uint32_
 			if (length >= 2 + param_position) {
 				event->set_pitch(data[param_position]);
 				event->set_velocity(data[param_position + 1]);
-
-				if (event->get_message() == MIDIMessage::NOTE_ON && event->get_velocity() == 0) {
-					// https://www.midi.org/forum/228-writing-midi-software-send-note-off,-or-zero-velocity-note-on
-					event->set_message(MIDIMessage::NOTE_OFF);
-				}
 			}
 			break;
 

doc/classes/InputEventMIDI.xml

@@ -90,7 +90,7 @@
 			The pressure of the MIDI signal. This value ranges from 0 to 127. For many devices, this value is always zero.
 		</member>
 		<member name="velocity" type="int" setter="set_velocity" getter="get_velocity" default="0">
-			The velocity of the MIDI signal. This value ranges from 0 to 127. For a piano, this corresponds to how quickly the key was pressed, and is rarely above about 110 in practice.
+			The velocity of the MIDI signal. This value ranges from 0 to 127. For a piano, this corresponds to how quickly the key was pressed, and is rarely above about 110 in practice. Note that some MIDI devices may send a [constant MIDI_MESSAGE_NOTE_ON] message with zero velocity and expect this to be treated the same as a [constant MIDI_MESSAGE_NOTE_OFF] message, but device implementations vary so Godot reports event data exactly as received.
 		</member>
 	</members>
 </class>