and implement it for ruma_api::error::FromHttpResponseError and Void.
This allows integrating EndpointErrors in the common rust error
ecosystem like thiserror and anyhow.
The Outgoing trait now has no attributes except incoming_no_deserialize,
it looks for any references and lifetimes in a struct declaration and
removes them. The point of the Outgoing trait is to allow references to
be serialized and owned values to come out of deserialization. It has no
ability to wrap values in Raw (then EventResult).
