Add a map method to Bound
Add a map method to Bound

Add a map method to std::ops::range::Bound, patterned off of the method
of the same name on Option

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