message: bzl rule: have one-liner with the doc summary separated.
diff: def std_move_parser_symbols(name, src, out):
  """Convert symbol assignments (=) to std::move.
  +
  transformations:
  *++yyvsp = yylval; -> *++yyvsp = std::move(yylval);
  *++yyvsp = yyval; -> *++yyvsp = std::move(yyval);
  