Deprecate dropdown

Author: lpsmith

reflex-dom-core/src/Reflex/Dom/Widget/Input.hs

@@ -429,6 +429,7 @@ regularToDropdownViewEventType en r = case en of
 --TODO: We should allow the user to specify an ordering instead of relying on the ordering of the Map
 -- | Create a dropdown box
 --   The first argument gives the initial value of the dropdown; if it is not present in the map of options provided, it will be added with an empty string as its text
+{-# DEPRECATED "Consider using 'selectElement' instead.  As-is, 'dropdown' has multiple interface and implementation issues; a revised version may appear in a forthcoming high-level widget library" #-}
 dropdown :: forall k t m. (DomBuilder t m, MonadFix m, MonadHold t m, PostBuild t m, Ord k) => k -> Dynamic t (Map k Text) -> DropdownConfig t k -> m (Dropdown t k)
 dropdown k0 options (DropdownConfig setK attrs) = do
   optionsWithAddedKeys <- fmap (zipDynWith Map.union options) $ foldDyn Map.union (k0 =: "") $ fmap (=: "") setK