citation-style-language/styles — pull request #915 by adunning (2014-04-12 09:12:21+00:00)
Title: Use plural abbreviation 'eds.' in CMoS author-date

It is specified in section 15.9 that the abbreviation in author-date when there are multiple editors is 'eds.' Please let me know if there is some other function for this, but I haven't been able to find it.