replace itrunc(Uint8, 1234) => mod(1234, Uint8), etc. [fix #8646]
itrunc => mod: a few more integer modulus methods.
integer trunction: use `n % T` instead of `mod(n, T)`.
fix inadvertently introduced type-change in `Uint128 * Uint128`.
Merge branch 'sk/modpocalypse'

Conflicts:
	base/deprecated.jl