cmd/compile: add short self-link to ABI spec
cmd/compile: add short self-link to ABI spec

This makes the short link discoverable.

Change-Id: I9a2f091652bc096feebbbd79a854aa68efe702bb
Reviewed-on: https://go-review.googlesource.com/c/go/+/394634
Trust: Austin Clements <7ea35d812706d9213868749011af1ed4fa2f6aa0@google.com>
Reviewed-by: Eli Bendersky‎ <e83e4a9813852caf164372e4b6bd506b7819d6ab@golang.org>

CAFxX/go,CAFxX/go,golang/go,golang/go,golang/go,nawawi/go,golang/go,nawawi/go,CAFxX/go,CAFxX/go,nawawi/go,golang/go,nawawi/go,nawawi/go,golang/go,nawawi/go,CAFxX/go,nawawi/go,CAFxX/go,golang/go,CAFxX/go,CAFxX/go,golang/go,nawawi/go