Fix <Menu> storybook is missing

packages/ra-ui-materialui/src/layout/Menu.stories.tsx

@@ -0,0 +1,88 @@
+import * as React from 'react';
+
+import { Resource, testDataProvider } from 'ra-core';
+import { defaultTheme, Admin } from 'react-admin';
+import { AppBar, Typography, Box } from '@mui/material';
+import { createTheme } from '@mui/material/styles';
+import { ToggleThemeButton } from '../button';
+import { Layout, Menu, SidebarToggleButton, Title } from '.';
+
+export default { title: 'ra-ui-materialui/layout/Menu' };
+
+const resources = ['Posts', 'Comments', 'Tags', 'Users', 'Orders', 'Reviews'];
+
+const DemoAppBar = props => {
+    const darkTheme = createTheme({
+        palette: { mode: 'dark' },
+    });
+    return (
+        <AppBar
+            {...props}
+            elevation={1}
+            sx={{ flexDirection: 'row', flexWrap: 'nowrap' }}
+        >
+            <Box sx={{ flex: '1 1 100%' }}>
+                <SidebarToggleButton />
+            </Box>
+            <Box sx={{ flex: '0 0 auto' }}>
+                <ToggleThemeButton
+                    lightTheme={defaultTheme}
+                    darkTheme={darkTheme}
+                />
+            </Box>
+        </AppBar>
+    );
+};
+
+const DemoList = ({ name }) => (
+    <>
+        <Title title={name} />
+        <Typography variant="h4">{name}</Typography>
+    </>
+);
+
+export const Default = () => {
+    const DefaultLayout = props => (
+        <Layout {...props} menu={MenuDefault} appBar={DemoAppBar} />
+    );
+    const MenuDefault = () => {
+        return <Menu hasDashboard={true} dense={false} />;
+    };
+
+    return (
+        <Admin dataProvider={testDataProvider()} layout={DefaultLayout}>
+            {resources.map((resource, index) => {
+                return (
+                    <Resource
+                        name={resource}
+                        key={`resource_${index}`}
+                        list={<DemoList name={resource} />}
+                    />
+                );
+            })}
+        </Admin>
+    );
+};
+
+export const Dense = () => {
+    const LayoutDense = props => (
+        <Layout {...props} menu={MenuDense} appBar={DemoAppBar} />
+    );
+    const MenuDense = props => {
+        return <Menu {...props} hasDashboard={true} dense={true} />;
+    };
+
+    return (
+        <Admin dataProvider={testDataProvider()} layout={LayoutDense}>
+            {resources.map((resource, index) => {
+                return (
+                    <Resource
+                        name={resource}
+                        key={`resource_${index}`}
+                        list={<DemoList name={resource} />}
+                    />
+                );
+            })}
+        </Admin>
+    );
+};