bench: Fix a few hlint warnings

tests/Data/BlockQueueSpec.hs

@@ -24,12 +24,12 @@ spec = do
 emptySpec :: Spec
 emptySpec = describe "empty" $ do
   it "creates an empty queue" $
-    property $ \sizes -> runST $ (empty sizes) >>= null
+    property $ \sizes -> runST $ empty sizes >>= null
 
-  it "creates a queue where no block is present" $ do
+  it "creates a queue where no block is present" $
     property $ \size -> runST $ do
       q <- empty size
-      all not <$> mapM (\b -> (Block b) `elem` q) [0..size-1]
+      all not <$> mapM (\b -> Block b `elem` q) [0..size-1]
 
 enqueueSpec :: Spec
 enqueueSpec = describe "enqueue" $ do