Auto merge of #29846 - JanLikar:#29823, r=steveklabnik
Auto merge of #29846 - JanLikar:#29823, r=steveklabnik

Fix #29823 by further explaining `&str` and pointing out the
difference between `&str` and `&'static str`.

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