This change was introduced while adding the dark copy
of golang.org/x/vgo in CL 118095.

While the comment made sense in a separate vgo repo, when it is
merged with the main repo, this should not remain.

Found while running mkalldocs.sh in CL 119695.

Change-Id: I112a4629c415032bd29e165ac1c27a0f3cabeede
Reviewed-on: https://go-review.googlesource.com/119938Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>