gofmt -r 'exportname(s) -> types.IsExported(s)'

Passes toolstash-check.

Change-Id: I6b428bd039c135be66d8b81c325d4e08bae69f24
Reviewed-on: https://go-review.googlesource.com/105938Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>