/termfreq paging is confusing

[jan-niestadt]

The /termfreq operation returns a page of results but doesn't indicate how many results there are in total. You can page through them using first and number, but if first is >= number of results, first is set to its default value 0.

http://svatai01.ivdnt.loc/blacklab-server/chn-refcorpus/termfreq?annotation=pos&number=10&first=100

Better would be to simply return an empty list when first is set too high. It would also be useful to report the total number of results in the response. Probably change this response in the new api V4 (/corpora/...)