Also add a few other missing constants.

Also rerun current version of stringer.

Change-Id: I004ef27f6b40fe2cab64c52d169255dfea43fa01
Reviewed-on: https://go-review.googlesource.com/c/go/+/175137
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>