Clean up hierarchy of rails

detector rail has fundamentally different functionality than activator and powered rails, so it's misleading to present the same APIs for both.
detector rail's 'powered' state is better referred to as 'activated', since it means the detector rail is actually _producing_ power, and not _receiving_ power.

src/block/ActivatorRail.php

@@ -23,7 +23,10 @@ declare(strict_types=1);
 
 namespace pocketmine\block;
 
-class ActivatorRail extends RedstoneRail{
+use pocketmine\block\utils\RailPoweredByRedstoneTrait;
+
+class ActivatorRail extends BaseRail{
+	use RailPoweredByRedstoneTrait;
 
 	//TODO
 }

src/block/DetectorRail.php

@@ -23,7 +23,29 @@ declare(strict_types=1);
 
 namespace pocketmine\block;
 
-class DetectorRail extends RedstoneRail{
+class DetectorRail extends BaseRail{
+	protected bool $activated = false;
+
+	public function isActivated() : bool{ return $this->activated; }
+
+	/** @return $this */
+	public function setActivated(bool $activated) : self{
+		$this->activated = $activated;
+		return $this;
+	}
+
+	protected function writeStateToMeta() : int{
+		return parent::writeStateToMeta() | ($this->activated ? BlockLegacyMetadata::REDSTONE_RAIL_FLAG_POWERED : 0);
+	}
+
+	public function readStateFromData(int $id, int $stateMeta) : void{
+		parent::readStateFromData($id, $stateMeta);
+		$this->activated = ($stateMeta & BlockLegacyMetadata::REDSTONE_RAIL_FLAG_POWERED) !== 0;
+	}
+
+	protected function getConnectionsFromMeta(int $meta) : ?array{
+		return self::CONNECTIONS[$meta & ~BlockLegacyMetadata::REDSTONE_RAIL_FLAG_POWERED] ?? null;
+	}
 
 	//TODO
 }

src/block/PoweredRail.php

@@ -23,5 +23,8 @@ declare(strict_types=1);
 
 namespace pocketmine\block;
 
-class PoweredRail extends RedstoneRail{
+use pocketmine\block\utils\RailPoweredByRedstoneTrait;
+
+class PoweredRail extends BaseRail{
+	use RailPoweredByRedstoneTrait;
 }

src/block/utils/PoweredByRedstoneTrait.php

@@ -0,0 +1,36 @@
+<?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;
+
+trait PoweredByRedstoneTrait{
+	protected bool $powered = false;
+
+	public function isPowered() : bool{ return $this->powered; }
+
+	/** @return $this */
+	public function setPowered(bool $powered) : self{
+		$this->powered = $powered;
+		return $this;
+	}
+}

src/block/utils/RailPoweredByRedstoneTrait.php

@@ -21,12 +21,12 @@
 
 declare(strict_types=1);
 
-namespace pocketmine\block;
+namespace pocketmine\block\utils;
 
-abstract class RedstoneRail extends BaseRail{
+use pocketmine\block\BlockLegacyMetadata;
 
-	/** @var bool */
-	protected $powered = false;
+trait RailPoweredByRedstoneTrait{
+	use PoweredByRedstoneTrait;
 
 	protected function writeStateToMeta() : int{
 		return parent::writeStateToMeta() | ($this->powered ? BlockLegacyMetadata::REDSTONE_RAIL_FLAG_POWERED : 0);