Set "screensaver" as synonym of "Screen saver" for Settings search.

Also set android:id attribute for Screen saver preference screen.
When the attribute is unset, the search result is removed.

Bug: 229106045
Fix: 229106045
Test: on device. Forced Settings search re-indexing.

Change-Id: Ibaff9baacb28ecc5b41ac9c1e264b4ab28a83ce9
diff --git a/res/xml/display_settings.xml b/res/xml/display_settings.xml
index 03d073b..0649eee 100644
--- a/res/xml/display_settings.xml
+++ b/res/xml/display_settings.xml
@@ -144,7 +144,8 @@
         <Preference
             android:key="screensaver"
             android:title="@string/screensaver_settings_title"
-            android:fragment="com.android.settings.dream.DreamSettings"/>
+            android:fragment="com.android.settings.dream.DreamSettings"
+            settings:keywords="@string/keywords_screensaver"/>
 
         <SwitchPreference
             android:key="camera_gesture"