[css-font-loading] typo

--HG--
extra : rebase_source : 545137e9f68bb71b781e83df98e54b22bcfc0978

Author: tabatkins

css-font-loading/Overview.bs

@@ -713,7 +713,7 @@ API Examples</h2>
 		To show content only after all font loads complete:
 
 		<pre>
-			document.FontFaceSet.ready().then(function() {
+			document.fonts.ready().then(function() {
 				var content = document.getElementById("content");
 				content.style.visibility = "visible";
 			});

css-font-loading/Overview.html

@@ -803,7 +803,7 @@ <h2 class="heading settled heading" data-level=5 id=font-load-event-examples><sp
 	<div class=example>
 		To show content only after all font loads complete:
 
-		<pre>  document.FontFaceSet.ready().then(function() {
+		<pre>  document.fonts.ready().then(function() {
     var content = document.getElementById("content");
     content.style.visibility = "visible";
   });