Add description to all the widgets in the Widget Catalog

A short description needs to be added to all the widgets present in the Widget Catalog. The description needs to be added in the `WidgetDescription` class under the dart file of that particular widget. For example, in Row Widget, a short description of what a row widget does needs to be added in the `RowDescription` class, which is present in the `row.dart` file in `lib\routes`.
Please attach a screenshot of your work.

Start by inspecting the WidgetDescription classes in the widget Dart files under lib/routes, using row.dart and RowDescription as the example. Find every widget represented in the Widget Catalog and confirm each has a short description. Verify the catalog displays the descriptions and attach a screenshot of the completed work.

Written by the indexing model from the issue text.