Add widget of the week videos (#34356)

* Spacer
* MediaQuery
* InheritedWidget

packages/flutter/lib/src/widgets/framework.dart

@@ -1545,6 +1545,8 @@ abstract class ParentDataWidget<T extends RenderObjectWidget> extends ProxyWidge
 /// for that inherited widget using [BuildContext.inheritFromWidgetOfExactType]
 /// and then returns the [ThemeData].
 ///
+/// {@youtube 560 315 https://www.youtube.com/watch?v=1t-8rBCGBYw}
+///
 /// See also:
 ///
 ///  * [StatefulWidget] and [State], for widgets that can build differently

packages/flutter/lib/src/widgets/media_query.dart

@@ -510,6 +510,8 @@ class MediaQueryData {
 /// exception, unless the `nullOk` argument is set to true, in which case it
 /// returns null.
 ///
+/// {@youtube 560 315 https://www.youtube.com/watch?v=A3WrA4zAaPw}
+///
 /// See also:
 ///
 ///  * [WidgetsApp] and [MaterialApp], which introduce a [MediaQuery] and keep

packages/flutter/lib/src/widgets/spacer.dart

@@ -33,6 +33,8 @@ import 'framework.dart';
 /// ```
 /// {@end-tool}
 ///
+/// {@youtube 560 315 https://www.youtube.com/watch?v=7FJgd7QN1zI}
+///
 /// See also:
 ///
 ///  * [Row] and [Column], which are the most common containers to use a Spacer