Potential fix for code scanning alert no. 1: Overly permissive regular expression range

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

sortable.js

 	}
 	if (itm == "") return; 
 	sortfn = ts_sort_caseinsensitive;
-	if (itm.match(/^\d\d[\/\.-][a-zA-z][a-zA-Z][a-zA-Z][\/\.-]\d\d\d\d$/)) sortfn = ts_sort_date;
+	if (itm.match(/^\d\d[\/\.-][a-zA-Z][a-zA-Z][a-zA-Z][\/\.-]\d\d\d\d$/)) sortfn = ts_sort_date;
 	if (itm.match(/^\d\d[\/\.-]\d\d[\/\.-]\d\d\d{2}?$/)) sortfn = ts_sort_date;
 	if (itm.match(/^-?[£$€Û¢´]\d/)) sortfn = ts_sort_numeric;
 	// ignore stuff in () after the numbers.