add @history[] lines for typed/racket/async-channel

Don't merge, but wanted to check that I'm using the `@history[]` form properly.

In particular, the note in `libraries.scrbl` gets compiled to

    Added in version 6.0.1.13 of package typed-racket-lib.

even though the library is part of `typed-racket-more`. But I'm not sure how to change that.