Further detail of the use of nanopublications for CiTO annotations

[egonw]

Does not fix anything but implements some extra detail of CiTO annotations from nanopublications.

Description

This patch adds two extra statistics lines, resulting in three nanopub related statistics:

• number of nanopublications with CiTO annotations (existing, but better description)
• number of CiTO annotations (new)
• number of articles with CITO annotations defined in nanopubs (new)

Caveats

None anticipated.

Check any of the following which apply:

• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update
  • [ ] I have made corresponding changes to the documentation
• [ ] This change requires new dependencies (please list)

Testing

• see the stats table at https://scholia.toolforge.org/cito/

Checklist

• [ ] I have commented my code, particularly in hard-to-understand areas
• [x] My changes generate no new warnings
• [x] I have not used code from external sources without attribution
• [ ] I have considered accessibility in my implementation
• [x] There are no remaining debug statements (print, console.log, ...)