I believe that the example now uses coroutines, but not asyncio, so it should work with a regular Twisted reactor.

PS: I used to mix the two of them as well until @kmike and @wRAR illuminated me.

I've read this article a few times, which shows how to use async/await independently from asyncio, but I still get confused sometimes. Might be time to read it again!
In any case, there is no Deferred in play anymore, that needs to be addressed.

The docs need an example of a spider with asynio enabled and used.

A simple spider does not require asyncio, and a complex spider would not make for a good example.

On the other hand, it may be useful to cover, for example, an example item pipeline that uses an asyncio-based SQL client to record items in a database.