Minor correction in `sort_by_key` doc comment
Minor correction in `sort_by_key` doc comment

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