message: XPath: Improve error message for expressions like .[1]
  W3C specification does not allow predicates after abbreviated steps.
  Currently this results in parsing terminating at the step, which leads
  to confusing error messages like "Invalid query" or "Unmatched braces".
diff: @@ -11398,12 +11398,18 @@ PUGI__NS_BEGIN
  {
  _lexer.next();
  + if (_lexer.current() == lex_open_square_brace)
  + return error("Predicates are not allowed after an abbreviated step");
  +
  return alloc_node(ast_step, set, axis_self, nodetest_type_node, 0);
  }
  else if (_lexer.current() == lex_double_dot)
  {
  _lexer.next();
  + if (_lexer.current() == lex_open_square_brace)
  + return error("Predicates are not allowed after an abbreviated step");
  +
  return alloc_node(ast_step, set, axis_parent, nodetest_type_node, 0);
  }
  