Revert "app/internal/xkb: fix duplicate edit events for special keys"

This reverts commit e84a2344cf.

The fix is wrong: it's supressing the release key.Event, not key.EditEvents.
The culprit is that Editor fails to ignore release events.

Updates gio#171

app/internal/xkb/xkb_unix.go

@@ -170,9 +170,7 @@ func (x *Context) DispatchKey(keyCode uint32, state key.State) (events []event.E
 		if sym == C.XKB_KEY_ISO_Left_Tab {
 			cmd.Modifiers |= key.ModShift
 		}
-		if state == key.Press {
-			events = append(events, cmd)
-		}
+		events = append(events, cmd)
 	}
 	C.xkb_compose_state_feed(x.compState, sym)
 	var str []byte