remove unused language extension

Author: ProofOfKeags

src/Crypto/Secp256k1.hs

@@ -2,7 +2,6 @@
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
-{-# LANGUAGE MultiWayIf #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE RecordWildCards #-}
 {-# LANGUAGE ScopedTypeVariables #-}