Add 'doctest' as a cabal test

We provide a simple wrapper that executes `doctest` on our `src`
directory. This allows us to run all doctests during a regular `cabal
test` run.

src/HCat/Internal.hs

@@ -4,8 +4,6 @@ module HCat.Internal where
 import Data.Text (Text)
 import Data.Text qualified as T
 
-import System.IO
-import System.Info qualified as SysInfo
 import System.Process qualified as P
 
 -- | @parseArgs@ takes a list of strings and returns a single FilePath if there was exactly one element.
@@ -72,28 +70,7 @@ paginate (ScreenDimensions rows cols) =
 type Pages = [Page]
 type Page = Text
 
-getTerminalSize :: IO ScreenDimensions
-getTerminalSize = case SysInfo.os of
-  "linux" -> tputScreenDimensions
-  "darwin" -> tputScreenDimensions
-  _ -> pure $ defaultScreenDimensions{screenRows = 25, screenColumns = 80}
-
-defaultScreenDimensions :: ScreenDimensions
-defaultScreenDimensions = ScreenDimensions{screenRows = 25, screenColumns = 80}
-
-tputScreenDimensions :: IO ScreenDimensions
-tputScreenDimensions = ScreenDimensions <$> tput "lines" <*> tput "cols"
+getScreenDimensions :: IO ScreenDimensions
+getScreenDimensions = ScreenDimensions <$> tput "lines" <*> tput "cols"
  where
   tput cmd = read <$> P.readProcess "tput" [cmd] ""
-
-data UserCommand = NextPage | Quit deriving (Show)
-
-getUserCommand :: IO UserCommand
-getUserCommand = do
-  hSetBuffering stdin NoBuffering
-  hSetEcho stdin False
-  input <- getChar
-  case input of
-    ' ' -> pure NextPage
-    'q' -> pure Quit
-    _ -> getUserCommand