stringer: fix sample generated code
stringer: fix sample generated code

Note to self: never hand-edit generated code.
This is the actual output from stringer.

Change-Id: I3900b790d2019afa5dc4ed55391d50cd4f772525
Reviewed-on: https://go-review.googlesource.com/1993
Reviewed-by: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>

jeffreyliguori/blog,gorakhargosh/blog,gorakhargosh/blog