cmd/godoc: add perf subrepo

For golang/go#14304.

Change-Id: Ia90193d3a9ad027231f977ffa6b66cf60ea40683
Reviewed-on: https://go-review.googlesource.com/34615
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
1 file changed