Method update

internal/mapper/mapper.path.go:85–88

(n *nodeRecord, newF float64)

	return n
}
func (pq *priorityQueue) update(n *nodeRecord, newF float64) {
	n.fScore = newF
	heap.Fix(pq, n.index)
}

// heuristic is the 3D Manhattan distance.
// This should be redone - rooms can be one space away exit-wise, but 2+ spacex in grid space.