code: function highlight( term, html, wrapperNode ) {
  	debug( 'Starting highlight' );
  	if ( ! wrapperNode ) {
  		wrapperNode = document.createElement( 'mark' );
  	}
  	if ( ! term || ! html ) {
  		return html;
  	}
  	const root = document.createElement( 'div' );
  	root.innerHTML = html;
  	walk( root, term, wrapperNode );
  	return root.innerHTML;
  }
docs: Wraps strings in a html to highlight
  @param {string} term Term to search for
  @param {string} html HTML string to search and wrap
  @param {HTMLElement} [wrapperNode] Custom node to wrap the elements with, defaults to <mark>
  @returns {string} Wrapped HTML