Auto merge of #74652 - poliorcetics:clarify-vec-drain-doc, r=jyn514
Auto merge of #74652 - poliorcetics:clarify-vec-drain-doc, r=jyn514

Improve the documentation for Vec::drain

Fixes #73844.

@rusbot modify labels: A-collections, C-enhancement, T-doc, T-libs

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