Quote from @spf13: "I also think it's the better default
and should continue to be the case going forward."
Also mention the use of `hugo config` to check the current value
of `canonifyurls`, thanks to suggestion by @bep.
Fixes#802
- Rejigged the weight of the extras/ content for the new crossreferences
page.
- Used the new {{</*…*/>}} format for documenting highlighting and to
prevent a warning about the missing `fig` shortcode.
Be able to inhibit AbsURL canonicalization of content, on a site
configuration basis. Advantages of being able to inhibit this include
making it easier to rendering on other hostnames, and being able to
include resources on http or https depending on how this page was
retrieved, avoiding mixed-mode client complaints without adding latency
for plain http.