Updated data tables documentation

Author: squidfunk

docs/reference/data-tables.md

@@ -134,7 +134,7 @@ loading] via [additional JavaScript]:
 
     ``` js
     document$.subscribe(function() {
-      var tables = document.querySelectorAll("article table")
+      var tables = document.querySelectorAll("article table:not([class])")
       tables.forEach(function(table) {
         new Tablesort(table)
       })