Level: Add API method getViewersForPosition()

This returns all players who have the given position within their view radius.

src/pocketmine/level/Level.php

@@ -595,6 +595,16 @@ class Level implements ChunkManager, Metadatable{
 		return $this->chunkLoaders[Level::chunkHash($chunkX, $chunkZ)] ?? [];
 	}
 
+	/**
+	 * Returns an array of players who have the target position within their view distance.
+	 * @param Vector3 $pos
+	 *
+	 * @return Player[]
+	 */
+	public function getViewersForPosition(Vector3 $pos) : array{
+		return $this->getChunkPlayers($pos->getFloorX() >> 4, $pos->getFloorZ() >> 4);
+	}
+
 	/**
 	 * Queues a DataPacket to be sent to all players using the chunk at the specified X/Z coordinates at the end of the
 	 * current tick.