ItemFactory: fix isRegistered() again

we really need to get rid of the ItemFactory legacy nasties so we can burn this code

src/block/utils/WallConnectionType.php

@@ -0,0 +1,48 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+ */
+
+declare(strict_types=1);
+
+namespace pocketmine\block\utils;
+
+use pocketmine\utils\EnumTrait;
+
+/**
+ * This doc-block is generated automatically, do not modify it manually.
+ * This must be regenerated whenever registry members are added, removed or changed.
+ * @see build/generate-registry-annotations.php
+ * @generate-registry-docblock
+ *
+ * @method static WallConnectionType NONE()
+ * @method static WallConnectionType SHORT()
+ * @method static WallConnectionType TALL()
+ */
+final class WallConnectionType{
+	use EnumTrait;
+
+	protected static function setup() : void{
+		self::registerAll(
+			new self("none"),
+			new self("short"),
+			new self("tall")
+		);
+	}
+}