try fixing windows tests

Author: wz1000

test/functional/Highlight.hs

@@ -10,7 +10,7 @@ import Test.Tasty.HUnit
 
 tests :: TestTree
 tests = testGroup "highlight" [
-    testCase "works" $ runSession hlsCommand fullCaps "test/testdata" $ do
+    testCase "works" $ runSession (hlsCommand ++ " --test") fullCaps "test/testdata" $ do
         doc <- openDoc "Highlight.hs" "haskell"
         _ <- waitForDiagnosticsFrom doc
         highlights <- getHighlights doc (Position 2 2)