Drop exponent suggestion when 0
Drop exponent suggestion when 0

This commit changes numeric literal formatting to drop exponent when
exponent is 0.

aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust