The time for scheme-relative URLs has passed.
go.dev, like all of .dev, is an HTTPS-only domain.
And golang.org has set HSTS headers for years too.
So these relative links are always going to be https:// on the internet.
When serving from http://localhost, they turn into http://,
which is never what we want.
So rewrite them all to hard-code https://.
Change-Id: I1c25108910a12f2974b8f6ba86d49d0b697516a4
Reviewed-on: https://go-review.googlesource.com/c/website/+/365099
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Jamal Carvalho <jamal@golang.org>
Russ Cox