function isTrailingCommaAllowed(lastItem) {
	return !(
		lastItem.type === "RestElement" ||
		lastItem.type === "RestProperty" ||
		lastItem.type === "ExperimentalRestProperty"
	);
}
Checks whether or not a trailing comma is allowed in a given node.
If the `lastItem` is `RestElement` or `RestProperty`, it disallows trailing commas.
@param {ASTNode} lastItem The node of the last element in the given node.
@returns {boolean} `true` if a trailing comma is allowed.