canonical links should be set to https

[sdarwin]

The canonical links appear to refer to "http". They should use "https".

<link rel="canonical" href="http://www.stage.boost.org/doc/libs/latest/doc/html/accumulators.html">

From https://developers.google.com/search/docs/crawling-indexing/consolidate-duplicate-urls#prefer-https-over-http-for-canonical-urls

"""
Prefer HTTPS over HTTP for canonical URLs

Google prefers HTTPS pages over equivalent HTTP pages as canonical, except when there are issues or conflicting signals

"""