Make sure that you can match on enum values

[Boddlnagg]

I'm not sure if the current implementation strategy allows using match for enum values. Should work for the variants with and without associated constants. I'm too lazy to test this right now, so just close this if it already works.

[Boddlnagg]

I just verified that everything works okay.

This is the variant with associated constants, which currently requires nightly:

let t = MidiMessageType::NoteOn;
match t {
    MidiMessageType::NoteOff => println!("off"),
    MidiMessageType::NoteOn => println!("on"),
    _ => ()
};

And this variant without associated constants results in warnings, but otherwise works as intended (also on stable):

let t = MidiMessageType_NoteOn;
match t {
    MidiMessageType_NoteOff => println!("off"),
    MidiMessageType_NoteOn => println!("on"),
    _ => ()
};

#[allow(non_upper_case_globals)] should be sufficient to silence these warnings:

warning: constant in pattern `MidiMessageType_NoteOff` should have an upper case name such as `MIDI_MESSAGE_TYPE_NOTE_OFF`, #[warn(non_upper_case_globals)] on by default
  --> examples\test.rs:41:9
   |
41 |         MidiMessageType_NoteOff => println!("off"),
   |         ^^^^^^^^^^^^^^^^^^^^^^^

warning: constant in pattern `MidiMessageType_NoteOn` should have an upper case name such as `MIDI_MESSAGE_TYPE_NOTE_ON`, #[warn(non_upper_case_globals)] on by default
  --> examples\test.rs:42:9
   |
42 |         MidiMessageType_NoteOn => println!("on"),
   |         ^^^^^^^^^^^^^^^^^^^^^^

[Boddlnagg]

The only possible pain point is that you can't use associated constants (yet), i.e.

use wrt::windows::devices::midi::MidiMessageType::NoteOff;

doesn't work (Not a moduleMidiMessageType``).