8334a58c2f
Add a lint for an async block/closure that yields a type that is itself awaitable.
This catches bugs of the form
tokio::spawn(async move {
let f = some_async_thing();
f // Oh no I forgot to await f so that work will never complete.
});
See the two XXXkhuey comments and the unfixed `_l` structure for things that need more thought.
*Please keep the line below*
changelog: none