Link documentation for the "Appearance" preference page

There is documentation available for the "Appearance" preference page
but it's help context was not added to this preference page. So if
a user pressed the "?" icon on the preference dialog this specific
documentation was not show.

bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/dialogs/ViewsPreferencePage.java

@@ -76,6 +76,7 @@
 import org.eclipse.ui.IWorkbenchPreferenceConstants;
 import org.eclipse.ui.IWorkbenchPreferencePage;
 import org.eclipse.ui.PlatformUI;
+import org.eclipse.ui.internal.IWorkbenchHelpContextIds;
 import org.eclipse.ui.internal.WorkbenchMessages;
 import org.eclipse.ui.internal.WorkbenchPlugin;
 import org.eclipse.ui.internal.themes.IThemeDescriptor;
@@ -116,6 +117,8 @@ public class ViewsPreferencePage extends PreferencePage implements IWorkbenchPre
 	protected Control createContents(Composite parent) {
 		initializeDialogUnits(parent);
 
+		PlatformUI.getWorkbench().getHelpSystem().setHelp(parent, IWorkbenchHelpContextIds.VIEWS_PREFERENCE_PAGE);
+
 		Composite comp = new Composite(parent, SWT.NONE);
 
 		themingEnabled = createCheckButton(comp, WorkbenchMessages.ThemingEnabled, engine != null);