Rename checked_add_duration to checked_add and make it take the duration by value
Rename checked_add_duration to checked_add and make it take the duration by value

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