Fix Try Dart handling of Backspace that joins lines

site/try/src/interaction_manager.dart

Index: site/try/src/interaction_manager.dart
diff --git a/site/try/src/interaction_manager.dart b/site/try/src/interaction_manager.dart
index 3776dc23014dc3cf52fde88b4c2757f84d77b426..2dc2aa8e820b380689a8109ca53540b60ef6afea 100644
--- a/site/try/src/interaction_manager.dart
+++ b/site/try/src/interaction_manager.dart
@@ -1234,7 +1234,7 @@ void normalizeMutationRecord(MutationRecord record,
     var first = record.removedNodes.first;
     var line = findLine(record.target);
 
-    if (first is Text && first.data=="\n" && line.nextNode != null) {
+    if (first is Text && line.nextNode != null) {
       normalizedNodes.add(line.nextNode);
     }
     normalizedNodes.add(line);