Only use nub on SrcSpan for ghc>=9

Author: anka-213

ghcide/src/Development/IDE/Plugin/CodeAction.hs

@@ -861,9 +861,14 @@ suggestImportDisambiguation df (Just txt) ps@(L _ HsModule {hsmodImports}) diag@
                     HideOthers restImports :
                     [ ToQualified parensed qual
                     | ExistingImp imps <- [modTarget]
+#if MIN_GHC_API_VERSION(9,0,0)
+                    {- HLINT ignore suggestImportDisambiguation "Use nubOrd" -}
                     -- TODO: The use of nub here is slow and maybe wrong for UnhelpfulLocation
                     -- nubOrd can't be used since SrcSpan is intentionally no Ord
                     , L _ qual <- nub $ mapMaybe (ideclAs . unLoc)
+#else
+                    , L _ qual <- nubOrd $ mapMaybe (ideclAs . unLoc)
+#endif
                         $ NE.toList imps
                     ]
                     ++ [ToQualified parensed modName