Removed a TODO item.
|* LRijkstra: see if the forward search could be removed by just adding|
|one more trie, rooted at the initial state, which covers all of the|
|* Another crazy idea: if we had a special "void" non-terminal symbol,|
|we could use it as a parameter, which would allow us to make extensible|
|definitions. (Any production that contains void would be removed after|