Add some javadoc, add container to callback

src/main/java/dev/zontreck/libzontreck/chestgui/IChestGUIButtonCallback.java

@@ -1,9 +1,18 @@
 package dev.zontreck.libzontreck.chestgui;
 
 import net.minecraft.world.item.ItemStack;
+import net.minecraftforge.items.ItemStackHandler;
 
+/**
+ * This should be used in place of Runnable for ChestGUI
+ */
 @FunctionalInterface
 public interface IChestGUIButtonCallback
 {
-    void run(ItemStack stack);
+    /**
+     * A callback function that when invoked will pass the ChestGUI ItemStack
+     * @param stack A temporary itemstack that is used for the ChestGUI
+     * @param container The container object for manipulating other items when this is invoked
+     */
+    void run(ItemStack stack, ItemStackHandler container);
 }