Fix -Wunused-packages in hls-cabal-plugin (haskell#3977)

Author: jhrcek

Diff for: plugins/hls-cabal-plugin/hls-cabal-plugin.cabal

@@ -20,7 +20,7 @@ extra-source-files:
   test/testdata/simple-cabal/simple-cabal.cabal
 
 common warnings
-  ghc-options: -Wall
+  ghc-options: -Wall -Wunused-packages
 
 library
   import:           warnings
@@ -80,15 +80,12 @@ test-suite tests
     , base
     , bytestring
     , Cabal-syntax          >= 3.7
-    , directory
     , filepath
-    , ghcide
     , hls-cabal-plugin
     , hls-test-utils    == 2.6.0.0
     , lens
     , lsp
     , lsp-types
-    , tasty-hunit
     , text
     , text-rope
     , transformers

Diff for: plugins/hls-cabal-plugin/src/Ide/Plugin/Cabal.hs

@@ -286,7 +286,7 @@ completion recorder ide _ complParams = do
     (Just cnts, Just path) -> do
       pref <- VFS.getCompletionPrefix position cnts
       let res = result pref path cnts
-      liftIO $ fmap (InL) res
+      liftIO $ fmap InL res
     _ -> pure . InR $ InR Null
  where
   result :: Maybe VFS.PosPrefixInfo -> FilePath -> VFS.VirtualFile -> IO [CompletionItem]

Diff for: plugins/hls-cabal-plugin/test/Context.hs

@@ -78,7 +78,7 @@ getContextTests =
         , testCase "Cabal version keyword - no value, many spaces" $ do
             -- on a file, where the "cabal-version:" keyword is already written
             -- the context should still be top level but the keyword should be recognized
-            ctx <- callGetContext (Position 0 45) ("") ["cabal-version:" <> T.replicate 50 " "]
+            ctx <- callGetContext (Position 0 45) "" ["cabal-version:" <> T.replicate 50 " "]
             ctx @?= (TopLevel, KeyWord "cabal-version:")
         , testCase "Cabal version keyword - keyword partly written" $ do
             -- in the first line of the file, if the keyword