Fix WordLadder (extension of [https://github.com/LeonGuertler/TextArena/pull/59](old pr))

[DylanASHillier]

WordLadder but more efficient and harder words

• depends slightly on the changes in env.utils.word_lists but a more general change

• fixes the graph algorithm to work better for hard words

• The old hard mode was actually easier than the easy mode because the adjacencies were found in the adjacency graph made from basic words only (thus more sparse)

• New mode uses larger list of words to determine adjacency...

• To do so uses more efficient algorithms

Examples before / after
Easy [before] gold -> band
['gold', 'cold', 'cord', 'card', 'hard', 'hand', 'band'] ❌ (intended)
['gold', 'bold', 'bond', 'band'] ✅ (easily found)
Easy [after] page -> mass
['page', 'pate', 'bate', 'bats', 'bass', 'mass']
Medium [before] sky -> law
['sky', 'say', 'ray', 'rat', 'cat', 'cut', 'nut', 'not', 'now', 'low', 'law'] ❌
['sky', 'say', 'lay', 'law'] ✅
Medium [after] work from ['work', 'cork', 'corp', 'coop', 'clop', 'flop', 'flog', 'frog', 'from']
Hard [before] rod -> cow
['rod', 'red', 'bed', 'bad', 'sad', 'say', 'ray', 'rat', 'cat', 'cut', 'nut', 'not', 'now', 'cow']❌
['rod', 'cod', 'cow'] ✅
Hard [after] shame -> loose
['shame', 'shale', 'stale', 'stile', 'stilt', 'stint', 'saint', 'paint', 'point', 'joint', 'joist', 'joust', 'roust', 'rouse', 'louse', 'loose']

[DylanASHillier]

Big question remains? should move the target path, start state, target state into the game state object right?