[css-transitions] Clarify what "otherwise" means in this context.

Author: dbaron

css-transitions/Overview.bs

@@ -1095,7 +1095,10 @@ url: http://w3c.github.io/dom/#constructing-events; type: dfn; text: event const
         to the set of <a>completed transitions</a>
         and then fire the <a href="#transition-events">events</a>
         for those completions.
-        <span class="note">(Note that doing otherwise could allow
+        <span class="note">(Note that doing otherwise, that is,
+        firing some of the events before doing all of the moving
+        from <a>running transitions</a> to <a>completed transitions</a>,
+        could allow
         a style change event to happen
         without the necessary transitions completing,
         since firing the event could cause a style change event,

css-transitions/Overview.html

@@ -1621,7 +1621,10 @@ <h2 class="heading settled" data-level="5" id="complete"><span class="secno">5.
         to the set of <a data-link-type="dfn" href="#completed-transition">completed transitions</a>
         and then fire the <a href="#transition-events">events</a>
         for those completions.
-        <span class="note" role="note">(Note that doing otherwise could allow
+        <span class="note" role="note">(Note that doing otherwise, that is,
+        firing some of the events before doing all of the moving
+        from <a data-link-type="dfn" href="#running-transition">running transitions</a> to <a data-link-type="dfn" href="#completed-transition">completed transitions</a>,
+        could allow
         a style change event to happen
         without the necessary transitions completing,
         since firing the event could cause a style change event,