Modules with Unsafe language pragmas can use "safe import"

If I use `stylish-haskell` on a module with
```
{-# LANGUAGE Unsafe #-} -- "import safe" is enforced
```
I still get the following error:
```
Language.Haskell.Stylish.Parse.parseModule: could not parse src/Extract/DefinitionsTheoremsLemmas.hs: ParseFailed (SrcLoc ".hs" 15 13) "At least one of Safe or SafeImports or Trustworthy language extensions needs to be enabled. Please add: {-# LANGUAGE Safe #-} or {-# LANGUAGE SafeImports #-} or {-# LANGUAGE Trustworthy #-} language pragma at the top of your module."
```
`Unsafe` is described [on the GHC wiki](https://ghc.haskell.org/trac/ghc/wiki/SafeHaskell).