[biblio.ref] Update URLs of css-backgrounds-4 and css-page-template-1

[tidoust]

This update adjusts the URLs of the entries for CSS Backgrounds and Borders Module Level 4 and CSS Pagination Templates Module Level 3, so that they target the final document directly; and refreshes the list of authors for CSS Backgrounds and Borders Module Level 4.

[svgeesus]

Thanks, but does anything use the ancient and unmaintained biblio ref file?

Bikeshed uses tobie/specref and CSS2 is in process of being updated to use Bikeshed so I don't think this file is used anymore.

[tidoust]

Well, Specref uses this "ancient and unmaintained" biblio ref file to build entries in csswg.json (and notably CSS3-PAGE-TEMPLATE and CSS4BACKGROUND) through the csswg.js script that runs every few hours.

Specref ignores most of the entries in biblio.ref because they are already defined elsewhere, typically because the specs have already been published to /TR/. It still relies on the info in this file for some entries.

[svgeesus]

Looking at the biblio.ref history with 4 edits in the last 4 years, syncing every few hours seems excessive.

I'm okay to merge this, but it seems better long-term to just add directly to specref.

I guess I should chat with @tobie about this.