internal/gen: bugfix: escape the escape character Change-Id: Ib39499508296af25c02a81aaf194b292bac17854 Reviewed-on: https://go-review.googlesource.com/30393 Run-TryBot: Marcel van Lohuizen <mpvl@golang.org> Reviewed-by: Nigel Tao <nigeltao@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>