text: Title: TST,DOC: Bump `scipy_doctest` (or remove pin) and fix new failures
  Body: @ev-br ping FYI,  since the new scipy-doctest release (less than an hour ago) the refcheck has universal failures.
  
  I suspect, this is all just bad documentation that needs fixing, but not sure yet.  In either case, until fixed both CircleCI and the "benchmark" tests which also still run the refcheck are expected to fail.
  
  (Currently, also the linter just started failing...)