The page about Furtle, a turtle graphics module, is 404 (https://docs.racket-lang.org/furtle/index.html). Does Furtle exist?
I assume you are talking about GitHub - souravdatta/furtle: A functional way of creating turtles ยท GitHub? I don't see it being registered in https://pkgs.racket-lang.org/ (or even the older https://planet.racket-lang.org/), so it makes sense that there's no global doc page under https://docs.racket-lang.org/. You also wouldn't be able to install it using raco pkg install <package-name>.
If you really want to use this particular package, you can clone the Git repo locally, and install it from source. It looks like Furtle does have a Scribble documentation, so you will also be able to view its documentation locally too after the installation.
Alternatively, if you just want a Turtle functionality, there are some other alternatives: