Add XStaticFile to Html document.

indexHtml :: Html ()
indexHtml = do
    doctypehtml_ do
        head_ do
            meta_ [charset_ "utf-8"]
            meta_ [name_ "viewport", content_ "width=device-width, initial-scale=1.0"]
            xstaticScripts xfiles
  where
    xfiles = XStatic.htmx : XStatic.xterm