Adding call_count to the docs.
Adding call_count to the docs.

derwiki-adroll/mock,fladi/mock,dannybtran/mock,rbtcollins/mock,johndeng/mock,pypingou/mock,testing-cabal/mock,OddBloke/mock,kostyll/mock,sorenh/mock,lord63-forks/mock,nett55/mock,scorphus/mock,frankier/mock