I was looking in the wrong area of the FARs:
(e) By using normal flight and power controls, except as otherwise noted in paragraphs (e)(1) and (e)(2) of this section, it must be possible to establish a zero rate of descent at an attitude suitable for a controlled landing without exceeding the operational and structural limitations of the airplane, as follows:
(1) For single-engine and multiengine airplanes, without the use of the primary longitudinal control system.
It's a requirement that it be possible in the plane, it's not a requirement to publish how, but Cessna does. But, to be clear, it doesn't say that you can do the controlled landing, just you can get to the plane to zero descent there! Worthy of a bit of careful practice, particularly for Cherokee pilots right now!