Make SGMenu's onClose consume an InventoryCloseEvent

[Ghosty920]

SpiGUI/src/main/java/com/samjakob/spigui/menu/SGMenu.java

Line 71 in c74b525

private Consumer<SGMenu> onClose;

onClose should be a Consumer<InventoryCloseEvent>
Giving the menu when we are literally calling the method with that same menu isn't helpful, using the event would be more, like for accessing the player and the inventory