start rewriting the parser to return with error messages so errors can be caught

src/parser/string/string.h

@@ -15,7 +15,7 @@ char *swap_quotes(char *input, char quote);
 
 char *unquote(char *str, size_t *decoded_len);
 
-ParsedValue *parse_string(Token* token, bool to_unquote);
+ParsedValueReturn parse_string(Token* token, bool to_unquote);
 
 void free_parsed_string(void *ptr);