Add highlight menu keys for all toggle pref controllers and custom slices

Bug: 204695404
Test: manual, robotest build pass, unit
Change-Id: Iad2e28ada8ddb766ffa7eff2c8dc581250cbd6f8

src/com/android/settings/display/AlwaysOnDisplaySlice.java

@@ -106,4 +106,9 @@ public class AlwaysOnDisplaySlice implements CustomSliceable {
     public Intent getIntent() {
         return null;
     }
+
+    @Override
+    public int getSliceHighlightMenuRes() {
+        return R.string.menu_key_display;
+    }
 }