[noise] minor suggestion: pre-message pattern instead of pre-message patternS ?

[David Wong]

> 1. the two pre-message patterns could be merged into one pre-message
> pattern where the responder tokens are represented as "rs" and "re". I
> know this would make the diagrams less nice, but this would make the
> code nicer.

Or to copy the handshake pattern inside the handshake pattern, a
single pre-message pattern could be a sequence of message pattern (one
-> and one <-)

David