simplify lifetime annotations for `MirBorrowckCtxt`
simplify lifetime annotations for `MirBorrowckCtxt`

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