Update variable declaration

Author: ismailuddin

doc/source/_static/js/whatsnew_links.js

@@ -1,8 +1,8 @@
 (function() {
 	const links = document.getElementsByTagName('a');
 	for (let i = 0; i < links.length; i++) {
+		const re = /(whatsnew.html)#(whatsnew)-[\d]+(-\w+)+/g;
 		let linkElements = links[i].href.split("/");		
-		var re = /(whatsnew.html)#(whatsnew)-[\d]+(-\w+)+/g;
 		if (re.test(linkElements.slice(-1)[0])) {
 			let whatsNew = linkElements.slice(-1)[0].split("#");
 			whatsNew = generateWhatsNew(whatsNew);