do not throw error when trying to match tag at the end of the document

lib/ace/editor.js

@@ -545,9 +545,12 @@ var Editor = function(renderer, session) {
                 return;
             }
             
-            if (token.type.indexOf("tag-open") != -1)
+            if (token.type.indexOf("tag-open") != -1) {
                 token = iterator.stepForward();
-
+                if (!token)
+                    return;
+            }
+            
             var tag = token.value;
             var depth = 0;
             var prevToken = iterator.stepBackward();