fix 8.6 build

Author: pepeiborra

ghcide/src/Development/IDE/Core/Tracing.hs

@@ -67,8 +67,11 @@ withTrace name act
       act setSpan'
   | otherwise = act (\_ _ -> pure ())
 
-withEventTrace :: (MonadMask m, MonadIO m) =>
-    String -> ((ByteString -> ByteString -> m ()) -> m a) -> m a
+#if MIN_VERSION_ghc(8,8,0)
+withEventTrace :: (MonadMask m, MonadIO m) => String -> ((ByteString -> ByteString -> m ()) -> m a) -> m a
+#else
+withEventTrace :: (MonadMask m, MonadIO m) => String -> ((String -> String -> m ()) -> m a) -> m a
+#endif
 withEventTrace name act
   | userTracingEnabled
   = withSpan (fromString name) $ \sp -> do