make Z.of_nat not a coercion inside std++
This takes a first step towards #102 by not declaring the coercion in std++. We will add it back in Iris. This can help gauge the fallout of #102, and it would have caught this problem.
This takes a first step towards #102 by not declaring the coercion in std++. We will add it back in Iris. This can help gauge the fallout of #102, and it would have caught this problem.