Fixed an issue with list indexes in fabricators.dm

I assumed that all lists would be 9 or less items for the proc, which was wrong. Was causing a runtime error, and preventing people from building a lot of stuff in the mech fabricator.
Proc now finds the first non-digit character, which allows for as large lists as possible.
Doesn't let you start a part_sets list with numbers, though, so don't do that. Inputs are fragile.