fix(decorators): don't do magic on __doc__ when sphinx is called

Otherwise donc cachedproperty.__doc__ returns "property" and not the expected docstring.
6 jobs for topic/default/fix-sphinx in 5 minutes and 32 seconds (queued for 42 seconds)
Status Job ID Name Coverage
  Tests
passed black #32597

00:01:29

passed check-manifest #32596

00:01:23

passed flake8 #32595

00:01:30

passed mypy #32598

00:02:03

passed py3 #32594

00:02:02

 
  After Tests
passed trigger-other-pipelines #32599

00:00:55