feat: Add an expression for normal distribution

[LiamGallagher737]

Describe the solution you'd like

I'd like to see a normal distribution equivalent to the existing uniform method.

Describe why you want that solution. Is this related to a problem?

If I could simply call a normal method (or some other name) on a ExprWriter, the code would be much easier to read than stacking uniform distributions or some other work around to this.

Describe alternatives you've considered

This is this solution posted by NiseVoid on the discord.

Additional context

This is the distribution I'm thinking of.