Rollup merge of #58317 - hayekr:patch-1, r=frewsxcv
Rollup merge of #58317 - hayekr:patch-1, r=frewsxcv

Some writing improvement, conciseness of intro

Made unstable-features doc more concise in the introduction paragraph

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