BlockGrowEvent: add player information for bonemeal usage (#5596)

this is in line with StructureGrowEvent, which also has a similar API.

src/event/block/BlockGrowEvent.php

@@ -23,9 +23,27 @@ declare(strict_types=1);
 
 namespace pocketmine\event\block;
 
+use pocketmine\block\Block;
+use pocketmine\player\Player;
+
 /**
  * Called when plants or crops grow.
  */
 class BlockGrowEvent extends BaseBlockChangeEvent{
 
+	public function __construct(
+		Block $block,
+		Block $newState,
+		private ?Player $player = null,
+	){
+		parent::__construct($block, $newState);
+	}
+
+	/**
+	 * It returns the player which grows the crop.
+	 * It returns null when the crop grows by itself.
+	 */
+	public function getPlayer() : ?Player{
+		return $this->player;
+	}
 }