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/development/transcode/TranscodeUserControlPreferenceController.java

@@ -19,6 +19,7 @@ package com.android.settings.development.transcode;
 import android.content.Context;
 import android.os.SystemProperties;
 
+import com.android.settings.R;
 import com.android.settings.core.TogglePreferenceController;
 
 /**
@@ -48,4 +49,9 @@ public class TranscodeUserControlPreferenceController extends TogglePreferenceCo
     public int getAvailabilityStatus() {
         return AVAILABLE;
     }
+
+    @Override
+    public int getSliceHighlightMenuRes() {
+        return R.string.menu_key_system;
+    }
 }