derive debug for event types

[sofoxe1]

currently to get unhandled event name one has to match for every event:

match event {
                xr::Event::SessionStateChanged(event) => {
                  info!("unknown event: SessionStateChanged");
                }
                xr::Event::InteractionProfileChanged(event) => {
                  info!("unknown event: InteractionProfileChanged");
                }
                ...
            }

this pr would allow for

match event {
                _ => {
                    info!("unknown event: {:?}",event);
                }
            }

or if less verbose output is desired

match event {
                _ => {
                    info!("unknown event: {}",event.name());
                }
            }

only testes if it builds but given what changed it should work
it's my first time using syn/quote so while this works there may be more "correct" way

[Ralith]

Seems reasonable.

[Ralith]

Please format conventionally.

[Ralith]

Prefer Ident::new(s, Span::call_site()).

[sofoxe1]

no idea what's the convention so i copied how event_decodes is done