[boost.async] new name

From: Klemens Morgenstern (klemensdavidmorgenstern_at_[hidden])
Date: 2023-10-12 00:51:15

Given the renaming requirement, I'd like to query the list if there
are any objections to any of the following names:

async.core
await
co_async / cosync
co20 / cor20

Thanks,

Klemens