[racket] Example in Docs

I am trying the examples in 4.1.  When rendered via the Scribble HTML button, the function my-helper is underlined in red.  What does that mean?

The mouse-over works, and check-syntax in the scrbl file draws the arrows that indicate that the function is in helper.rkt. When I use raco setup, the documentation appears to be correct (but my-helper has a red line).

rac


manual.scrbl:

#lang scribble/manual
@(require (for-label racket
                    "helper.rkt"))

@title{My Library}

@defmodule[my-lib/helper]

@defproc[(my-helper [lst list?])
        (listof
         (not/c (one-of/c 'cow)))]


helper.rkt:

#lang racket

(provide/contract
[my-helper (-> list? (listof (not/c (one-of/c 'cow))))])

(define (my-helper lst) '(whatever))


info.rkt:

#lang setup/infotab
(define scribblings '(("manual.scrbl" ())))