unicode/norm: fix naming issue of example Change-Id: I1cba68281c18adaf571e0dbdc4ad37698d313a5b Reviewed-on: https://go-review.googlesource.com/38361 Run-TryBot: Marcel van Lohuizen <mpvl@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>