Provide TryBot test coverage in x/website using Go 1.16
while that version is still used during its deployment.

For golang/go#51800.

Change-Id: I4b1361537a8af8322ec62c86891de46143758c4e
Reviewed-on: https://go-review.googlesource.com/c/build/+/393858
Trust: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>

Updates golang/go#51800.
Updates golang/go#57217.

Change-Id: I9049457e8e69e4f6c35810998bbff2f8371078e1
Reviewed-on: https://go-review.googlesource.com/c/build/+/456655
Reviewed-by: Michael Pratt <mpratt@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>

Now that it's available, start deploying with it.

For golang/go#51800.

Change-Id: I11c4dc131e33f192e9d7ea1fb5a154fc3422dece
Reviewed-on: https://go-review.googlesource.com/c/website/+/456521
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>

Now that the deploy happens with Go 1.19, it's viable to start using
these packages from the standard library instead of their backported
temporary copies.

Keeping Go 1.18 happy during its last two months of support requires
a tiny complication in pkgdoc package. An alternative path is to not
drop internal/backport/go/doc and all of its dependencies right away,
but getting to zero backported packages sooner was hard to resist...

For golang/go#51800.

Change-Id: Ieb7a137a033d6b6850dfc019c8c0c767756cc30d
Reviewed-on: https://go-review.googlesource.com/c/website/+/456522
Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Bypass: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>

Testing x/website on Go 1.16.15 was helpful only until App Engine
started supporting¹ a currently-supported Go version like Go 1.19.

This undoes the change added in CL 393858, to be submitted around
the same time as x/website/cmd/golangorg/app.yaml's runtime value
goes from go116 to go119 or so.

¹ https://cloud.google.com/appengine/docs/standard/go/release-notes#December_07_2022

For golang/go#51800.

Change-Id: I621833060a160abf1fccdeb5b331582651eabc14
Reviewed-on: https://go-review.googlesource.com/c/build/+/456715
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>

This build should be passing on x/website as of CL 456517.

Updates golang/go#51800.
Updates golang/go#57217.

Change-Id: Iff8b8e6600bf15625e994d6ae398eda170c991dc
Reviewed-on: https://go-review.googlesource.com/c/build/+/457555
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Bryan Mills <bcmills@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>