Avoid rolling our own string literal parser.

🎩 @patrickt.

semantic-core/src/Data/Core/Parser.hs

@@ -110,14 +110,8 @@ lit = let x `given` n = x <$ reserved n in choice
   , Core.bool False `given` "#false"
   , Core.unit       `given` "#unit"
   , record
-  , token (between (string "\"") (string "\"") (Core.string . fromString <$> many (escape <|> (noneOf "\"" <?> "non-escaped character"))))
+  , Core.string <$> stringLiteral
   ] <?> "literal"
-  where escape = char '\\' *> choice
-          [ '"'  <$ string "\""
-          , '\n' <$ string "n"
-          , '\r' <$ string "r"
-          , '\t' <$ string "t"
-          ] <?> "escape sequence"
 
 record :: (TokenParsing m, Monad m) => m (Term Core User)
 record = Core.record <$ reserved "#record" <*> braces (sepEndBy ((,) <$> identifier <* symbolic ':' <*> expr) comma)