Rollup merge of #89303 - guswynn:std_suspend, r=dtolnay

Add `#[must_not_suspend]` to some types in std

I am not sure what else should have it? `Ref`?

library/std/src/lib.rs

@@ -297,6 +297,7 @@
 #![feature(maybe_uninit_slice)]
 #![feature(maybe_uninit_uninit_array)]
 #![feature(min_specialization)]
+#![cfg_attr(not(bootstrap), feature(must_not_suspend))]
 #![feature(needs_panic_runtime)]
 #![feature(negative_impls)]
 #![feature(never_type)]