Function absorb_radix_bits 

pub const fn absorb_radix_bits<F: PrimeField32>() -> u32

Bit length of F::ORDER_U32 - 1, i.e. the smallest b with F::ORDER_U32 - 1 < 2^b.

Used for tight base-$2^b$ absorb packing so canonical PrimeField32 digits are always valid base-$2^b$ digits (more limbs per PrimeField slot than radix $2^{32}$ when ORDER_U32 < 2^{32}).