Implementation of string is not ideal

[natefaubion]

purescript-parsing/src/Text/Parsing/Parser/String.purs

Lines 40 to 50 in f8dae05

	string :: forall s m. StringLike s => Monad m => String -> ParserT s m String
	string str = do
	input <- gets \(ParseState input _ _) -> input
	case indexOf (wrap str) input of
	Just 0 -> do
	modify_ \(ParseState _ position _) ->
	ParseState (drop (length str) input)
	(updatePosString position str)
	true
	pure str
	_ -> fail ("Expected " <> show str)

This will perform a linear scan to find a match anywhere, before checking if that match is at index 0. It should probably just take whatever the length of the desired token is and check for eq.