`divMod` was added to std.bigint.

$(REF divMod, std, bigint) calculates both the quotient and the remainder in one go:

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void divMod(const BigInt dividend, const BigInt divisor, out BigInt quotient, out BigInt remainder) pure nothrow
{
auto a = BigInt(123);
auto b = BigInt(25);
BigInt q, r;

divMod(a, b, q, r);

assert(q == 4);
assert(r == 23);
assert(q * b + r == a);
}
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