zuse: make it clear where the secp jet should make explicit size checks
zuse: make it clear where the secp jet should make explicit size checks

Well-behaved secp jets can now plausibly exit if they are given inputs
of the wrong size/range. Previously this was either not checked or the inputs
were silently truncated.

ngzax/urbit,ngzax/urbit,urbit/urbit,ngzax/urbit,urbit/urbit,urbit/urbit,ngzax/urbit,urbit/urbit,ngzax/urbit,ngzax/urbit,urbit/urbit,ngzax/urbit,urbit/urbit,urbit/urbit