ACTION-266: Validate ucr with pubrules

- preliminary PubRules testing started, Dave Ragett contacted to resolve issues with varying number of errors with [1] and [2]

[1] https://www.w3.org/pubrules/?url=https%3A%2F%2Frawgit.com%2Fw3c%2Fdxwg%2Fucr_profile_requirements%2Fucr%2Findex.html&profile=WG-NOTE&validation=simple-validation&noRecTrack=true&informativeOnly=true&echidnaReady=false&patentPolicy=pp2004

[2] https://www.w3.org/pubrules/?url=https%3A%2F%2Fraw.githubusercontent.com%2Fw3c%2Fdxwg%2Fucr_profile_requirements%2Fucr%2Findex.html&profile=WG-NOTE&validation=simple-validation&noRecTrack=true&informativeOnly=true&echidnaReady=false&patentPolicy=pp2004

Required to export and check the ReSpec-rendered static snapshot as of [1].
Syntax errors and broken links tested with PubRules [2] and validator [3],
fixed, as far as possible. Some caused by stale SpecRef entries [4].
Remaining issues (versioned URI, status statement) are expected to be added as part of the publication process.

[1] https://github.com/w3c/respec/wiki/ReSpec-Editor's-Guide#creating-a-static-snapshot

[2] https://www.w3.org/pubrules/?url=https%3A%2F%2Fraw.githubusercontent.com%2Fw3c%2Fdxwg%2Fucr_profile_requirements%2Fucr%2Fstatic%2Findex.html&profile=WD&validation=simple-validation&noRecTrack=false&informativeOnly=false&echidnaReady=false&patentPolicy=pp2004

[3] https://validator.w3.org/checklink?uri=https://raw.githack.com/w3c/dxwg/ucr_profile_requirements/ucr/static/index.html&recursive=on

[4] https://www.specref.org/?q=Bibliographic%20Ontology%20Specification