Rollup merge of #33565 - Amanieu:once_doc, r=GuillaumeGomez
Rollup merge of #33565 - Amanieu:once_doc, r=GuillaumeGomez

Fix typo in std::sync::Once documentation

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