Replace calls to Item#isInCreativeTab(...) with a direct check, fixes metadata items not being displayed correctly in the creative inventory

src/main/java/electroblob/wizardry/item/ItemArcaneTome.java

@@ -26,7 +26,7 @@ public class ItemArcaneTome extends Item {
 
 	@Override
 	public void getSubItems(CreativeTabs tab, NonNullList<ItemStack> list){
-		if (isInCreativeTab(tab)) {
+		if(tab == WizardryTabs.WIZARDRY){ // Don't use isInCreativeTab here.
 			for(int i = 1; i < Tier.values().length; i++){
 				list.add(new ItemStack(this, 1, i));
 			}

src/main/java/electroblob/wizardry/item/ItemScroll.java

@@ -39,7 +39,7 @@ public class ItemScroll extends Item {
 
 	@Override
 	public void getSubItems(CreativeTabs tab, NonNullList<ItemStack> list){
-		if(isInCreativeTab(tab)){
+		if(tab == WizardryTabs.SPELLS){
 			// In this particular case, getTotalSpellCount() is a more efficient way of doing this since the spell instance
 			// is not required, only the id.
 			for(int i = 0; i < Spell.getTotalSpellCount(); i++){

src/main/java/electroblob/wizardry/item/ItemSpellBook.java

@@ -36,7 +36,7 @@ public class ItemSpellBook extends Item {
 
 	@Override
 	public void getSubItems(CreativeTabs tab, NonNullList<ItemStack> list){
-		if(isInCreativeTab(tab)) {
+		if(tab == WizardryTabs.SPELLS){
 			// In this particular case, getTotalSpellCount() is a more efficient way of doing this since the spell instance
 			// is not required, only the id.
 			for(int i = 0; i < Spell.getTotalSpellCount(); i++){