Update library/alloc/src/string.rs
Update library/alloc/src/string.rs

Co-authored-by: LingMan <ef3b631cd556390efb05c4a02027db243470284b@users.noreply.github.com>
aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust