src/generators/dom/preprocess.js/preprocessChildren
function preprocessChildren ( generator, block, node ) {
	// glue text nodes together
	const cleaned = [];
	let lastChild;

	node.children.forEach( child => {
		if ( child.type === 'Comment' ) return;

		if ( child.type === 'Text' && lastChild && lastChild.type === 'Text' ) {
			lastChild.data += child.data;
			lastChild.end = child.end;
		} else {
			cleaned.push( child );
		}

		lastChild = child;
	});

	node.children = cleaned;

	cleaned.forEach( child => {
		const preprocess = preprocessors[ child.type ];
		if ( preprocess ) preprocess( generator, block, child );
	});
}