Move Browser search description to bookmarks search.

Before, android:searchSettingsDescription was set in searchable.xml,
but not in bookmarks_searchable.xml, which is the one that
is used from global search.

Fixes http://b/issue?id=1971319
"Description string for Browser source not showing in settings"
diff --git a/res/xml/bookmarks_searchable.xml b/res/xml/bookmarks_searchable.xml
index bc6ac93..de56add 100644
--- a/res/xml/bookmarks_searchable.xml
+++ b/res/xml/bookmarks_searchable.xml
@@ -22,6 +22,7 @@
     android:imeOptions="actionGo"
 
     android:includeInGlobalSearch="true"
+    android:searchSettingsDescription="@string/search_settings_description"
     android:searchSuggestAuthority="browser"
     android:searchSuggestPath="bookmarks"
     android:searchSuggestSelection="url LIKE ?"
diff --git a/res/xml/searchable.xml b/res/xml/searchable.xml
index a3b2d90..bb578c6 100644
--- a/res/xml/searchable.xml
+++ b/res/xml/searchable.xml
@@ -27,7 +27,6 @@
     android:inputType="textUri"
     android:imeOptions="actionGo"
     
-    android:searchSettingsDescription="@string/search_settings_description"
     android:searchSuggestAuthority="browser"
     android:searchSuggestSelection="url LIKE ?"
     android:searchSuggestIntentAction="android.intent.action.VIEW"