Asymptotics of gaussianReal

Stream: Is there code for X?

[Joris van Winden]

Does mathlib have following asymptotic for the cdf of the standard Gaussian measure?

I need the fact that $P (Z \geq a) \sim a^{-1} \exp (-a^2 / 2)$ as $a \to \infty$, when $Z$ has a standard normal distribution.