Use the first paragraph, instead of cookie-cutter text, for rustdoc descriptions
Use the first paragraph, instead of cookie-cutter text, for rustdoc descriptions

Fixes #82283

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