docstring for await_next_request_body

[tadad]

resolves #66

[nick1udwig]

This doesn't tell me, the consumer of the API, that if the next Message is not a Request then it will be dropped.

More generally I support @dr-frmr s recommendation to change this function to await_next_message_body() or the like to avoid the unintuitive behavior of dropping the Message entirely. That solution is better than documenting this because it avoids the situation entirely -- whereas the documentation solution requires that a dev reads and understands this footgun.

[nick1udwig]

Apologies for the changing target here.

[nick1udwig]

Please address comment, then good to go 👍

We'll have to remember to update any processes/scripts that make use of this function when we bump their process_lib version. I know I've seen it in a number of scripts -- and I use it in kit as well now.