Add "Addition of hidden word caused a word-doubling event" logic to main retry loop

[jonadsimon]

Currently even when the board is successfully constructed, it's possible for the addition of the hidden word to introduce a last-minute word-doubling. Rather than crashing, this should re-enter the retry loop since likely another solution can be found.

Example: python make_puzzle_v2.py "hamburger" "annihilation" --packing-constant=1.22 --strategy=median --pivot=max_freq --optimize-words