normalDistribution doesn't handle edge cases ±∞ #10965
Description
The standard normal CDF, 𝛷, maps [-∞,∞] to [0,1] with 𝛷(-∞) = 0, and 𝛷(∞) = 1. std.mathspecial.normalDistribution implements 𝛷, but normalDistribution(±real.infinity) returns NaN. Please extend it so that normalDistribution(-real.infinity) == 0 and normalDistrubtion(real.infinity) == 1.