Add support for post qualified import formatting.

[jhmcstanton]

Adds an option to use post qualified module imports.

Related to #284
Resolves #334

Let me know if any more tests or changes are needed.

[jhmcstanton]

This ghc_lib_parser option was removed since it is not used.

[jhmcstanton]

Not sure what the issue is with that mac build, classic case of "works on my machine". Not sure that I have access to rerun the build though, can someone with access trigger that for me (or show me how) ?

[akrmn]

This is exactly what I'm looking for right now.

It seems like the build error is the same one I got on #337, @jaspervdj, could we ignore it again for this PR?

[akrmn]

hm, this seems to fail on post qualified explicit imports:

import Data.Aeson qualified as JSON (Value)

gives me:

RealSrcSpan SrcSpanOneLine "./test.hs": parse error on input `qualified'

I'll add a few failing test cases later today

[akrmn]

Suggested change

	]
	, testCase "case 34" case34
	, testCase "case 35" case35
	, testCase "case 36" case36
	, testCase "case 37" case37
	]

[akrmn]

Suggested change

	]
	]
	--------------------------------------------------------------------------------
	case34 :: Assertion
	case34 = assertSnippet (step Nothing defaultOptions {postQualified = True})
	[ "import qualified Data.Aeson as JSON (Value)"
	]
	[ "import Data.Aeson qualified as JSON (Value)"
	]
	--------------------------------------------------------------------------------
	case35 :: Assertion
	case35 = assertSnippet (step Nothing defaultOptions {postQualified = True})
	[ "import Data.Aeson qualified as JSON (Value)"
	]
	[ "import Data.Aeson qualified as JSON (Value)"
	]
	--------------------------------------------------------------------------------
	case36 :: Assertion
	case36 = assertSnippet (step Nothing defaultOptions {postQualified = True})
	[ "import qualified Data.Aeson as JSON (Value)"
	, "import qualified Data.Aeson as JSON (encode, decode)"
	]
	[ "import Data.Aeson qualified as JSON (Value, decode, encode)"
	]
	--------------------------------------------------------------------------------
	case37 :: Assertion
	case37 = assertSnippet (step Nothing defaultOptions {postQualified = True})
	[ "import Data.Aeson qualified as JSON (Value)"
	, "import Data.Aeson qualified as JSON (encode, decode)"
	]
	[ "import Data.Aeson qualified as JSON (Value, decode, encode)"
	]

[akrmn]

@jhmcstanton I've also added these changes as a PR to your branch, in case that's easier to work with

[EncodePanda]

@jhmcstanton would it be much work now to rebase this against main?