docs: Fixing links to moved Fragments guide, + redirect

The Fragments API guide was moved, but apparently a redirect was
never set up. Also, there are a few links to the old location in
the Javadocs.

Staged the revised Javadocs (see first comment for stage location).
Not going to stage the redirects file since it would trash another,
bigger CL that deals with the redirects file, but it's pretty
straightforward.

bug: 30559011
Change-Id: Ibd65f85c1ebb9789c1d40614fe11fe4ffda97e58

core/java/android/app/Fragment.java

@@ -194,7 +194,7 @@ final class FragmentState implements Parcelable {
  * <div class="special reference">
  * <h3>Developer Guides</h3>
  * <p>For more information about using fragments, read the
- * <a href="{@docRoot}guide/topics/fundamentals/fragments.html">Fragments</a> developer guide.</p>
+ * <a href="{@docRoot}guide/components/fragments.html">Fragments</a> developer guide.</p>
  * </div>
  *
  * <a name="OlderPlatforms"></a>

core/java/android/app/FragmentManager.java

@@ -59,7 +59,7 @@ import java.util.List;
  * <div class="special reference">
  * <h3>Developer Guides</h3>
  * <p>For more information about using fragments, read the
- * <a href="{@docRoot}guide/topics/fundamentals/fragments.html">Fragments</a> developer guide.</p>
+ * <a href="{@docRoot}guide/components/fragments.html">Fragments</a> developer guide.</p>
  * </div>
  *
  * While the FragmentManager API was introduced in

core/java/android/app/package.html

@@ -34,7 +34,7 @@ action bar.</p>
 <p>For information about using some the classes in this package, see the following
 documents: <a href="{@docRoot}guide/topics/fundamentals/activities.html">Activities</a>, <a
 href="{@docRoot}guide/topics/fundamentals/services.html">Services</a>, <a
-href="{@docRoot}guide/topics/fundamentals/fragments.html">Fragments</a>, <a
+href="{@docRoot}guide/components/fragments.html">Fragments</a>, <a
 href="{@docRoot}guide/topics/ui/actionbar.html">Using the Action Bar</a>, <a
 href="{@docRoot}guide/topics/ui/dialogs.html">Creating Dialogs</a>, and <a
 href="{@docRoot}guide/topics/ui/notifiers/index.html">Notifying the User</a>.</p>

docs/html/_redirects.yaml

@@ -1,6 +1,8 @@
 # For information about this file's format, see
 # https://developers.google.com/internal/publishing/redirects
 redirects:
+- from: /guide/topics/fundamentals/fragments.html
+  to: /guide/components/fragments.html
 - from: /about/versions/index.html
   to: /about/index.html
 - from: /about/versions/api-levels.html