doc: update go1.11.html with user annotation API additions
doc: update go1.11.html with user annotation API additions

Change-Id: I357eea0efb04392e1a4671d20190a2052bf548de
Reviewed-on: https://go-review.googlesource.com/124706
Reviewed-by: Andrew Bonventre <682ad9f487f614f19e8b7cc5d340bdc8e1c1b128@golang.org>

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