`box::help` does not work on aliases of attached names

[Konrad Rudolph]

MWE

# foo.r

#' This is a test
#' @export
bar = function () 'hi'

box::use(./foo[baz = bar])
box::help(baz)

Observed result

Error in box::help(baz) :
  no documentation available for “baz” in module “./foo”

Expected behaviour

Display the documentation of foo$bar.

[Konrad Rudolph]

• Related: #330