fix error when inserting text inside code

lib/ace/edit_session/fold_line.js

@@ -192,13 +192,15 @@ function FoldLine(foldData, folds) {
     };
 
     this.split = function(row, column) {
-        var fold = this.getNextFoldTo(row, column).fold;
+        var pos = this.getNextFoldTo(row, column);
+        
+        if (!pos || pos.kind == "inside")
+            return null;
+            
+        var fold = pos.fold;
         var folds = this.folds;
         var foldData = this.foldData;
-
-        if (!fold)
-            return null;
-
+        
         var i = folds.indexOf(fold);
         var foldBefore = folds[i - 1];
         this.end.row = foldBefore.end.row;