function is_element_node(node) {
	return element_nodes.includes(node.type);
}
Returns true for all nodes that can appear elsewhere than the top level, have attributes and can contain children
@param {AST.SvelteNode} node
@returns {node is AST.Component | AST.RegularElement | AST.SlotElement | AST.SvelteComponent | AST.SvelteElement | AST.SvelteFragment | AST.SvelteSelf}