Rollup merge of #31762 - tshepang:in-which-case, r=steveklabnik
Rollup merge of #31762 - tshepang:in-which-case, r=steveklabnik

doc: there is no case that is shown, so something was likely missing …

…from the change

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