message: Update README with tsx code block
diff: @@ -19,16 +19,18 @@ export { shortcutsPlugin } from '@backstage/plugin-shortcuts';
  Add the `<Shortcuts />` component within your `<Sidebar>`:
  -```ts
  +```tsx
  import { Sidebar, SidebarDivider, SidebarSpace } from '@backstage/core';
  import { Shortcuts } from '@backstage/plugin-shortcuts';
  +export const SidebarComponent = () => (
  <Sidebar>
  {/* ... */}
  <SidebarDivider />
  <Shortcuts />
  <SidebarSpace />
  -</Sidebar>;
  + </Sidebar>
  +);
  ```
  The plugin exports a `shortcutApiRef` but the plugin includes a default implementation of the `ShortcutApi` that uses `localStorage` to store each user's shortcuts.
  