Fix pkgdown configuration for reference

[maelle]

Some topics are missing from the configuration file.

 Error in check_missing_topics(rows, pkg) : 
  All topics must be included in reference index
• Missing topics: osf_cp, osfr-package

Note that for topics you do not want to include in the index you can create an "internal" section https://pkgdown.r-lib.org/reference/build_reference.html?q=internal#missing-topics

To check all topics are listed, after editing the configuration file you can run pkgdown::check_pkgdown().

[maelle]

@aaronwolen in case you missed this (not that urgent but probably easy to fix)

[aaronwolen]

Thank you for reporting @maelle! I'll try to get that fixed.

[maelle]

Thank you!

[aaronwolen]

Fixed in #147