doc/go1.12: release notes for "go doc -all"
doc/go1.12: release notes for "go doc -all"

Change-Id: If65518c76a865c03266be76b1c21c76e1c8b4763
Reviewed-on: https://go-review.googlesource.com/c/153828
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

cloudflare/go,nawawi/go,nawawi/go,golang/go,akutz/go,cloudflare/go,CAFxX/go,nawawi/go,cloudflare/go,akutz/go,josharian/go,CAFxX/go,josharian/go,golang/go,josharian/go,nawawi/go,akutz/go,CAFxX/go,akutz/go,CAFxX/go,josharian/go,golang/go,nawawi/go,CAFxX/go,josharian/go,josharian/go,nawawi/go,cloudflare/go,akutz/go,cloudflare/go,CAFxX/go,golang/go,golang/go,nawawi/go,akutz/go,cloudflare/go,cloudflare/go,golang/go,nawawi/go,josharian/go,CAFxX/go,josharian/go,cloudflare/go,golang/go,CAFxX/go,akutz/go,akutz/go,golang/go