Address some Foldable documentation nits
Recent discussions on the haskell-cafe list have suggested possible improvements to the Data.Foldable documentation. This MR aims to address some of the critiques.
While "the patient is on the operating table", if anyone else has suggestions for improvements, this could be a good opportunity to further refine the exposition.
Links to rendered copies of: Data.Foldable, Data.Traversable and Prelude
Tracking: #17929
Edited by Hécate Kleidukos