public AttributedVertex addVertex(String id) {
		return addVertex(id, id);
	}
Adds a new vertex with the given id.  The vertex's name will be the same as the id.
If a vertex already exists with that id,
then that vertex will be returned.

@param id the unique vertex id that the graph should have a vertex for.
@return either an existing vertex with that id, or a newly added vertex with that id
Ghidra/Framework/Graph/src/main/java/ghidra/service/graph/AttributedGraph.java