Arrow functions with single expression bodies were parsed with a wrong
precedence level, causing comma expressions to be greedily consumed.

-- Testcase --
{%
	print({
		a: () => 1,
		b: () => 2
	}, "\n");
%}
-- End --

-- Expect stdout --
{ "a": "() => { ... }", "b": "() => { ... }" }
-- End --