doc: update go1.11 release notes
doc: update go1.11 release notes

Change-Id: I3e2a19fe90334f0c1ed1593c7a9a3a458f15d8e8
Reviewed-on: https://go-review.googlesource.com/124799
Reviewed-by: Andrew Bonventre <682ad9f487f614f19e8b7cc5d340bdc8e1c1b128@golang.org>

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