Add accessibility color inversion help resources to link to existing help page.

Bug: 151604096
Bug: 150873532
Test: manual test
Change-Id: Ie042d822de3ff5017548b8d92c74b208ee1f3a02

src/com/android/settings/accessibility/ToggleColorInversionPreferenceFragment.java

@@ -113,6 +113,11 @@ public class ToggleColorInversionPreferenceFragment extends ToggleFeaturePrefere
         super.onPause();
     }
 
+    @Override
+    public int getHelpResource() {
+        return R.string.help_url_color_inversion;
+    }
+
     @Override
     public void onSettingsClicked(ShortcutPreference preference) {
         super.onSettingsClicked(preference);