Tactics.IData: fix idata parser
Tactics.IData: fix idata parser

The index type needs to be parsed at a size smaller than ArrSize, because
otherwise it includes the -> Set and then the parse fails looking for
another arrow. I don't understand why this was changed, so I am rolling
it back. Perhaps it should be changed to parse at |pred ArrSize| instead.

kwangkim/pigment,kwangkim/pigment,kwangkim/pigment,brixen/Epigram