Update 'Material Components widgets' page with missing widgets

[feinstein]

Page URL: https://docs.flutter.dev/ui/widgets/material
Page source: https://github.com/flutter/website/tree/master/src/docs/development/ui/widgets/material.md

Description of issue:

• MaterialBanner is missing
• NavigationRail is missing

[micpap25]

@sfshaza2 what category would this fall into? Alerts, information displays, etc...

[guidezpl]

I wonder if we should rather deprecate this page in favor using Dartdoc categories/images to improve https://api.flutter.dev/flutter/material/material-library.html?

One less place to keep components in sync (the other being flutter/gallery).

[atsansone]

The Widget Catalog for Material3 has been updated and is in sync with the Material3 documentation. Navigation Rail is present but Material Banner is not. See #8574. Closing this issue as complete.