Avoid dodgy Rep (..) import in Cabal-syntax

Fixes #9070.

Author: RyanGlScott

Cabal-syntax/src/Distribution/Compat/Prelude.hs

@@ -248,7 +248,7 @@ import Data.Word (Word, Word16, Word32, Word64, Word8)
 import Distribution.Compat.Binary (Binary (..))
 import Distribution.Compat.Semigroup (Semigroup (..), gmappend, gmempty)
 import Distribution.Compat.Typeable (TypeRep, Typeable, typeRep)
-import GHC.Generics (Generic, K1 (unK1), M1 (unM1), Rep (..), U1 (U1), V1, (:*:) ((:*:)), (:+:) (L1, R1))
+import GHC.Generics (Generic (..), K1 (unK1), M1 (unM1), U1 (U1), V1, (:*:) ((:*:)), (:+:) (L1, R1))
 import System.Exit (ExitCode (..), exitFailure, exitSuccess, exitWith)
 import Text.Read (readMaybe)