Update short names in a yspec object
update_short(spec, ...)a yspec object
`<column name> = <short name>` pairs
If no update items are passed in, the original spec object will be returned. An error will be issued if a column update is requested, but can't be found in the spec.
sp <- ys_help$spec()
sp2 <- update_short(sp, ID = "subject", ALB = "serum albumin")