Fixup rest of the PR

lib/GHCup/Errors.hs

@@ -134,13 +134,12 @@ instance Pretty AlreadyInstalled where
   pPrint (AlreadyInstalled tool ver') =
     text [i|#{tool}-#{prettyShow ver'} is already installed|]
 
--- | The Directory for isolated install already exists and is not empty
--- | This is done to prevent any overwriting
-data IsolatedDirNotEmpty = IsolatedDirNotEmpty {path :: FilePath}
+-- | The Directory is supposed to be empty, but wasn't.
+data DirNotEmpty = DirNotEmpty {path :: FilePath}
 
-instance Pretty IsolatedDirNotEmpty where
-  pPrint (IsolatedDirNotEmpty path) = do
-    text [i| The directory for isolated install already exists and is NOT EMPTY : #{path}|]
+instance Pretty DirNotEmpty where
+  pPrint (DirNotEmpty path) = do
+    text [i|The directory was expected to be empty, but isn't: #{path}|]
 
 -- | The tool is not installed. Some operations rely on a tool
 -- to be installed (such as setting the current GHC version).