::expect does not format.

[luukvanderduim]

In the code base we can find multiple occurrences of eg.:

let serde_val = serde_plain::to_string(&iface).expect("Unable to serialize {iface}");

or

let encoded = to_bytes(ctxt, &from_role).expect("Unable to encode {from_role}");

However, .expect() does not support inserting and formatting variables.
Also, inclusion of {err} is unnecessary because expect will append the error automatically:

See: playground example

And the std rust docs on Result::expect

"What were they thinking?"

Note the guidelines on the message itself in the link above.
The expect message should contain the reason or assumption why we expect Result::Ok().

Could we adopt this guidance, to help us or future developers, as when debugging it may help to learn about the rationale why we thought - at time of writing - this was okay.

Thoughts?

[TTWNO]

Interestingly, there is no clippy lint for this, but there is a proposal for one.