remove duplicated authors in aliases

[DanChaltiel]

Whenever you use a single page for multiple functions (using @rdname), the authors automatically stack.

However, especially with aliases, it seems quite unlikely that there are different authors using the same documentation page.

Shouldn't duplicates be removed from this field?

I'm not sure how multi-author statements can be managed though (last example).

Here is a reproducible example:

#' foobar
#' @export
#' @author Agent Smith
foobar = function() print('foobar')

#' @rdname foobar
#' @export
#' @author Agent Smith
foo = function() print('foo')

#' @rdname foobar
#' @export
#' @author Dan Onino
bar = foo

[hadley]

Would you be interested in doing PR for this? I think it should be straightforward since you should just be able to copy what some other de-duplicating tag does?

[DanChaltiel]

This will still require a deep dive inside the code of roxygen2. This sounds interesting though so I'd be happy to make a PR as soon as I get the time to put into this, but I cannot say how long it would take.