[plt-scheme] Entering unicode characters in the REPL?

Hi,

In v372 you could enter unicode characters directly into the REPL like this:

> \u2665
♥

The docs (doc/guide/strings.html) say you can still do this in 4.x,
but when I try it in 4.0.2 in module I mode I get the error:

reference to an identifier before its definition: u2665

> (display "\u2665") ; This way still works
♥

Which one is right? (or what did I do wrong?)