Only use nub on SrcSpan for ghc>=9

Author: anka-213

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

@@ -869,9 +869,14 @@ suggestImportDisambiguation df (Just txt) ps@(L _ HsModule {hsmodImports}) diag@
             , mode <-
                 [ 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