return #createStack() & #createSnapshot() with deprecation

Author: MrHell228

src/main/java/org/spongepowered/api/item/inventory/ItemStack.java

@@ -121,6 +121,14 @@ static ItemStack of(ItemType itemType) {
      */
     void setQuantity(int quantity) throws IllegalArgumentException;
 
+    /**
+     * @deprecated Use {@link #asImmutable()} instead.
+     */
+    @Deprecated(forRemoval = true)
+    default ItemStackSnapshot createSnapshot() {
+        return this.asImmutable();
+    }
+
     /**
      * Returns true if the specified {@link ItemStack} has the same stack
      * size, {@link ItemType}, and data. Note that this method is not an

src/main/java/org/spongepowered/api/item/inventory/ItemStackSnapshot.java

@@ -45,6 +45,14 @@ static ItemStackSnapshot empty() {
         return Sponge.game().factoryProvider().provide(Factory.class).empty();
     }
 
+    /**
+     * @deprecated Use {@link #asMutable()} or {@link #asMutableCopy()} instead.
+     */
+    @Deprecated(forRemoval = true)
+    default ItemStack createStack() {
+        return this.asMutable();
+    }
+
     interface Factory {
 
         ItemStackSnapshot empty();