Rollup merge of #75967 - aticu:blackbox_typo, r=Dylan-DPC
Rollup merge of #75967 - aticu:blackbox_typo, r=Dylan-DPC

Fix typo in `std::hint::black_box` docs

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