godoc: Restore anchors for variables and constants

godoc once again adds anchors for variable and constant
declarations. Individual declarations and lists of declarations are
both covered.

Fixes golang/go#19894

Change-Id: If5f8f0c3429774f33535e2e654685ba5d71937f1
Reviewed-on: https://go-review.googlesource.com/40300
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2 files changed