Clarify the optional parameters for path nodes

[heyx3]

There are four booleans -- inertia, longest, edges, vertices. All of which default to false. What do they do?

[kaya3]

I have some comments on these here:

    /// <summary>
    /// If <c>true</c>, the path-finding algorithm will greedily avoid changing
    /// direction, when this does not lead to a longer path; i.e. the 'pen' has
    /// inertia. Otherwise, when multiple directions lead to equal shortest
    /// paths, one is chosen at random independently of previous steps.
    /// </summary>
    bool inertia;
    
    /// <summary>
    /// If <c>true</c>, the start position furthest from an end position will
    /// be chosen when finding a path. Otherwise, the start position nearest to
    /// an end position will be chosen.
    /// </summary>
    bool longest;
    
    /// <summary>If <c>true</c>, paths may include diagonal steps in two dimensions.</summary>
    bool edges;
    
    /// <summary>If <c>true</c>, paths may include diagonal steps in three dimensions.</summary>
    bool vertices;

[heyx3]

Thanks for making that repo!