Make cider-doc-handler work synchronously, and rename it
Extract `cider-doc-buffer-for'

And use it in `cider-complete-at-point'.
Make cider--jump-to-def-eval-fn work synchronously
Move find-tag-marker-ring insertion to cider-jump-to-def-for
cider--jump-to-def-eval-fn-1: signal errors
Define cider-company-location

It's a hack, but a simple one.
Define cider-company-docsig
Mention company-mode and company-cider
Upcase the argument name
Add Changelog entry
cider-company-location: check explicitly for namespace error message