Function short_of 

pub fn short_of(id: &str) -> &str

The short form of a run id: the trailing block after the last -.

A free function as well as RunState::short, because callers that have only an id - an error message, a daemon status, a route handler - were otherwise reimplementing the split, and two spellings of “short id” is one rename away from branch names that no longer match their run.