Niche plugin docs checks

[joemull]

Content needed

There are several plugins that only Andy (or maybe Mauro) knows about. We probably need Andy to check and supplement the docs for these plugins to make sure they are accurate. This is a catch-all issue for those.

Note

This issue is not for plugins that have already been checked or have other open issues. It's for the remaining ones that I can't list because I do not know about them.

• discovery and archiving plugins are covered in Documentation for discovery and archiving plugins #272
• books is covered in Updates to books plugin #270
• customstyling, imports, and consortial_billing have been covered in Docs content that needs developer input #241
• Isolinear is covered in: Isolinear - docs #261