Clarify IO usage via Applicative interface in Handlers, whitespace cleanup, remove dedicated source file for 404 view

src/Core/Rendering.hs

@@ -21,6 +21,6 @@ mdFileToLucid :: FilePath -> IO (LU.Html ())
 mdFileToLucid path = fmap (mdToLucid . decodeUtf8) (B.readFile path)
 
 mdFileToText :: FilePath -> IO (Text)
-mdFileToText path = do 
+mdFileToText path = do
   htmlContent <- mdFileToLucid path
   return $ toStrict $ LU.renderText htmlContent