Rollup merge of #75038 - rust-lang:Havvy-patch-1, r=steveklabnik
Rollup merge of #75038 - rust-lang:Havvy-patch-1, r=steveklabnik

See also X-Link mem::{swap, take, replace}

Since it's easy to end up at one of these functions when you really wanted the other one, cross link them with descriptions of why you'd want to use them.

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