Specify type returned when awaiting a oneshot::Receiver

[rukai]

Motivation

1

Currently the docs makes it sound like .awaiting the oneshot::Receiver directly returns T.
This is however not the case.

If you know what you are doing you can check the impl Future for Receiver but its a little hidden.

2

Additionally the docs for RecvError dont mention when the error is returned, which adds to the confusion around errors here.

Solution

1

I changed the phrase value to refer to the specific type, with a link to the RecvError docs.
The rendering of the adjacent code blocks is slightly wonky, but its good enough I think.

I welcome suggestions for alternative approaches to make this clearer.

2

Added a sentence to the RecvError docs explaining when its returned.

[Darksonn]

Thanks.