ensmallen uses the term "neighbors" for directed graphs in a non-standard way

[cmungall]

For directed graphs, the term neighbors is used in a non-standard way

E.g.
https://www.cs.cmu.edu/afs/cs/academic/class/15210-f14/www/lectures/graph-intro.pdf

Neighbors. A vertex u is a neighbor of (or equivalently adjacent to) a vertex v in a graph
G = (V, E) if there is an edge {u, v} ∈ E. For a directed graph a vertex u is an in-neighbor of
a vertex v if (u, v) ∈ E and an out-neighbor if (v, u) ∈ E. We also say two edges or arcs are
neighbors if they share a vertex

So I would understand neighbors to mean the union of in and out neighbors, but ensmallen uses neighbors to mean out-neighbors.

I don't think the method name should change as that would break code, but I think there should be a simple glossary published in this repo that explains the terminology in the methods