[cssom-view] Update element scroll steps to use new tuple value

Author: AtkinsSJ

cssom-view-1/Overview.bs

@@ -2362,8 +2362,8 @@ Whenever an element gets scrolled (whether in response to user interaction or by
     for the element with the element's <a spec="css-scroll-snap-2">eventual snap target</a> in the block axis
     as newBlockTarget and the element's <a spec="css-scroll-snap-2">eventual snap target</a> in the inline axis
     as newInlineTarget.
-1. If the element is already in <var>doc</var>'s <a>pending scroll events</a>, abort these steps.
-1. Append the element to <var>doc</var>'s <a>pending scroll events</a>.
+1. If (<var>element</var>, <code>"scroll"</code>) is already in <var>doc</var>'s <a>pending scroll events</a>, abort these steps.
+1. Append (<var>element</var>, <code>"scroll"</code>) to <var>doc</var>'s <a>pending scroll events</a>.
 
 Whenever a <a>visual viewport</a> gets scrolled (whether in response to user interaction or by an API), the user agent must run these steps: