update comments

cmd/internal/markov/dot/nodes_edges.go

@@ -45,8 +45,6 @@ func (n *Node) DOTID() string {
 // weightedLine is a DOT-aware multi.WeightedLine. By being a
 // multi.WeightedLine, it allows for self-loops, which are important for
 // absorbing Markov chains.
-// TODO: this is a little confusing, maybe just have checks in the code that
-// there's only one line in each edge?
 type weightedLine struct {
 	multi.WeightedLine
 }