Avoid incomplete record update in Haddock Hoogle

This commit avoids running into an incomplete record update warning
in the Hoogle backend of Haddock.

This was only noticed now, because incomplete record updates were broken
in GHC 9.6. Now that they are fixed, we have to avoid running into them!

haddock-api/src/Haddock/Backends/Hoogle.hs

@@ -192,7 +192,7 @@ pp_sig dflags names (L _ typ)  =
 
 -- note: does not yet output documentation for class methods
 ppClass :: DynFlags -> TyClDecl GhcRn -> [(Name, DocForDecl Name)] -> [String]
-ppClass dflags decl subdocs =
+ppClass dflags decl@(ClassDecl {}) subdocs =
     (ppDecl ++ ppTyFams) : ppMethods
   where
     ppDecl :: String
@@ -234,7 +234,7 @@ ppClass dflags decl subdocs =
         , nest 4 . vcat . map (Outputable.<> semi) $ elems
         , rbrace
         ]
-
+ppClass _ _non_cls_decl _ = []
 
 ppFam :: DynFlags -> FamilyDecl GhcRn -> [String]
 ppFam dflags decl@(FamilyDecl { fdInfo = info })