Rollup merge of #58565 - thomaseizinger:typo-future-docs, r=frewsxcv
Rollup merge of #58565 - thomaseizinger:typo-future-docs, r=frewsxcv

Fix typo in std::future::Future docs

I am not quite sure if this is actually a typo but

1. to me the sentence doesn't make sense if it says "expect"
2. I hope that `Future`s are not really allowed to cause memory unsafety if they are polled after completion.

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