Readme.md: fix test result

[savemejeff]

When parsing input03, the parser2 won't report syntax error until it reachs the plus sign.

struct ASTnode *additive_expr(void) {
  struct ASTnode *left, *right;
  int tokentype;

  left = multiplicative_expr();

  tokentype = Token.token;
  if (tokentype == T_EOF)
    return (left);

  // Cache the '+' or '-' token type
  /** here the actual cached token is int literal '34' **/

  while (1) {
    // Fetch in the next integer literal
    scan(&Token);
    /** scan()s plus sign **/

    right = multiplicative_expr(); 
    /** primary() reports syntax error since Token is T_PLUS **/

    left = mkastnode(arithop(tokentype), left, right, 0);

    tokentype = Token.token;
    if (tokentype == T_EOF)
      break;
  }

  return (left);
}

[savemejeff]

After a second thought, I think it may better to fix the parser2 itself, not the test result