Take out the Hamlet newline configuration since it actually doesn't affect the output. Like, at all.

src/Settings.hs

@@ -19,9 +19,8 @@ import Data.Yaml                  (decodeEither')
 import Database.Persist.MySQL     (MySQLConf (..))
 import Language.Haskell.TH.Syntax (Exp, Name, Q)
 import Network.Wai.Handler.Warp   (HostPreference)
-import Text.Hamlet                (HamletSettings(hamletNewlines), NewlineStyle(AlwaysNewlines), defaultHamletSettings)
 import Yesod.Default.Config2      (applyEnvValue, configSettingsYml)
-import Yesod.Default.Util         (WidgetFileSettings(wfsHamletSettings), widgetFileNoReload,
+import Yesod.Default.Util         (WidgetFileSettings, widgetFileNoReload,
                                    widgetFileReload)
 import qualified Database.MySQL.Base as MySQL
 
@@ -124,7 +123,7 @@ instance FromJSON AppSettings where
 --
 -- https://github.com/yesodweb/yesod/wiki/Overriding-widgetFile
 widgetFileSettings :: WidgetFileSettings
-widgetFileSettings = def { wfsHamletSettings = defaultHamletSettings { hamletNewlines = AlwaysNewlines } }
+widgetFileSettings = def
 
 -- | How static files should be combined.
 combineSettings :: CombineSettings