Avoid duplicating tag ID runtime and remove a superflous </dd> tag.
Found by https://validator.w3.org
Change-Id: I9c84b8257acbb6d3d6817192bb8d355207944b9a
Reviewed-on: https://go-review.googlesource.com/c/go/+/413254
Auto-Submit: Ian Lance Taylor <iant@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>