sub :: Markup n a -> Markup (FastMarkup n) a
sub m = case runMarkup m of
  (a, fm) -> a <$ lift (Hole Don'tEscape fm)

--------------------------------------------------------------------------------
-- 'Note' system
sub :: Markup n a -> Markup (FastMarkup n) a
sub m = case runMarkup m of
  (a, fm) -> a <$ lift (Hole Don'tEscape fm)

--------------------------------------------------------------------------------
-- 'Note' system
sub m = case runMarkup m of
  (a, fm) -> a <$ lift (Hole Don'tEscape fm)

--------------------------------------------------------------------------------
-- 'Note' system