Remove superfluous :GRAY assignment in depth first visit

[monora]

Discussed in #65

^{Originally posted by delphaber October 12, 2022}
Isn't line 200 superfluous? We are already marking the vertex as :GRAY in line 192 when we go deeper in the recursion level at line 201.

Just wondering if I'm missing something :)

rgl/lib/rgl/traversal.rb

Lines 191 to 201 in 3cdf5c2

	def depth_first_visit(u, vis = DFSVisitor.new(self), &b)
	vis.color_map[u] = :GRAY
	vis.handle_examine_vertex(u)
	each_adjacent(u) do |v|
	vis.handle_examine_edge(u, v)
	if vis.follow_edge?(u, v) # (u,v) is a tree edge
	vis.handle_tree_edge(u, v) # also discovers v
	vis.color_map[v] = :GRAY # color of v was :WHITE
	depth_first_visit(v, vis, &b)