NCC audit: Document that the choice of nonsquare for λ_G in \crossref{concretegrouphashpallasandvesta} makes no difference to the output of map_to_curve_simple_swu.
NCC audit: Document that the choice of nonsquare for λ_G in \crossref{concretegrouphashpallasandvesta} makes no difference
to the output of map_to_curve_simple_swu.

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

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