hls-refactor-plugin: More predictable hole fit for test

Now that we limit number of hole fits recommended by GHC, the test that
hopes to find `+` being recommended for `Int -> Int -> Int` becomes
unpredictable because there are too many symbols which match that type
and the sorting has little control over which symbols get recommended.

There are way fewer matches for `(Int -> Maybe Int) -> Maybe Int ->
Maybe Int`, so it makes the test consistently succeed.

plugins/hls-refactor-plugin/test/Main.hs

@@ -2653,16 +2653,16 @@ fillTypedHoleTests = let
   , testSession "filling infix type hole uses infix operator" $ do
       let mkDoc x = T.unlines
               [ "module Testing where"
-              , "test :: Int -> Int -> Int"
-              , "test a1 a2 = a1 " <> x <> " a2"
+              , "test :: Int -> Maybe Int -> Maybe Int"
+              , "test a ma = (a +) " <> x <> " ma"
               ]
       doc <- createDoc "Test.hs" "haskell" $ mkDoc "`_`"
       _ <- waitForDiagnostics
       actions <- getCodeActions doc (Range (Position 2 16) (Position 2 19))
-      chosen <- pickActionWithTitle "replace _ with (+)" actions
+      chosen <- pickActionWithTitle "replace _ with (<$>)" actions
       executeCodeAction chosen
       modifiedCode <- documentContents doc
-      liftIO $ mkDoc "+" @=? modifiedCode
+      liftIO $ mkDoc "<$>" @=? modifiedCode
   ]
 
 addInstanceConstraintTests :: TestTree