Change the notation \mathcal{I}^D_i for a Sapling Pedersen generator to \mathcal{I}(D, i).
Change the notation \mathcal{I}^D_i for a Sapling Pedersen generator to \mathcal{I}(D, i).

Signed-off-by: Daira Hopwood <cd7d43d5556a38ce626d53826fddc46adc597539@jacaranda.org>

zcash/zips,zcash/zips,zcash/zips,zcash/zips