Fix missed documentation change

By: md_5 <git@md-5.net>

paper-api/src/main/java/org/bukkit/inventory/meta/CrossbowMeta.java

@@ -29,7 +29,7 @@ public interface CrossbowMeta extends ItemMeta {
      *
      * @param projectiles
      * @throws IllegalArgumentException if one of the projectiles is not an
-     * arrow
+     * arrow or firework rocket
      */
     void setChargedProjectiles(@Nullable List<ItemStack> projectiles);