Rollup merge of #72563 - RalfJung:multi-return, r=matthewjasper
Rollup merge of #72563 - RalfJung:multi-return, r=matthewjasper

multiple Return terminators are possible

@ecstatic-morse mentioned in https://github.com/rust-lang/rust/issues/72515 that multiple `Return` terminators are possible. Update the docs accordingly.

Cc @rust-lang/wg-mir-opt

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