Fixes some comments

todoapp/app/build.gradle

@@ -47,7 +47,7 @@ android {
         }
     }
 
-    // Always show the onTasksResult of every unit test, even if it passes.
+    // Always show the result of every unit test, even if it passes.
     testOptions.unitTests.all {
         testLogging {
             events 'passed', 'skipped', 'failed', 'standardOut', 'standardError'

todoapp/app/src/main/java/com/example/android/architecture/blueprints/todoapp/TasksTabletNavigator.java

@@ -25,7 +25,6 @@
 /**
  * Manages screens in tablet mode.
  */
-
 public class TasksTabletNavigator {
 
     private final FragmentActivity mFragmentActivity;

todoapp/app/src/main/java/com/example/android/architecture/blueprints/todoapp/taskdetail/TaskDetailFragment.java

@@ -77,7 +77,10 @@ public View onCreateView(LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
         View root = inflater.inflate(R.layout.taskdetail_frag, container, false);
         setHasOptionsMenu(true);
-        // TODO: why are we retaining
+
+        // Retain the fragment to persist the presenter and its state.
+        // This means that it won't be recreated on a configuration change, but
+        // it's dangerous as it can produce bugs and leaks. Use it wisely.
         setRetainInstance(true);
         mDetailTitle = (TextView) root.findViewById(R.id.task_detail_title);
         mDetailDescription = (TextView) root.findViewById(R.id.task_detail_description);

todoapp/app/src/main/java/com/example/android/architecture/blueprints/todoapp/tasks/TasksFragment.java

@@ -106,7 +106,9 @@ public View onCreateView(LayoutInflater inflater, ViewGroup container,
                              Bundle savedInstanceState) {
         View root = inflater.inflate(R.layout.tasks_frag, container, false);
 
-        // Retain the fragment to persist the presenter and its state. Use it wisely.
+        // Retain the fragment to persist the presenter and its state.
+        // This means that it won't be recreated on a configuration change, but
+        // it's dangerous as it can produce bugs and leaks. Use it wisely.
         setRetainInstance(true);
 
         // Set up tasks view
@@ -148,7 +150,7 @@ public void onClick(View v) {
                 ContextCompat.getColor(getActivity(), R.color.colorPrimaryDark)
         );
         // Set the scrolling view in the custom SwipeRefreshLayout.
-        swipeRefreshLayout.setScrollUpChild(listView);
+        swqipeRefreshLayout.setScrollUpChild(listView);
 
         swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
             @Override