Doc fixes (#35892)

* Fixed assets embedding

* ++

* Completed snippet audit

* Analyzer

packages/flutter/lib/src/painting/text_style.dart

@@ -130,14 +130,10 @@ const String _kColorBackgroundWarning = 'Cannot provide both a backgroundColor a
 /// ```
 /// {@end-tool}
 ///
-/// {@tool sample}
-///
 /// Examples of the resulting heights from different values of `TextStyle.height`:
 ///
 /// ![Text height comparison diagram](https://flutter.github.io/assets-for-api-docs/assets/painting/text_height_comparison_diagram.png)
 ///
-/// {@end-tool}
-///
 /// ### Wavy red underline with black text
 ///
 /// {@tool sample}

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

@@ -4713,13 +4713,14 @@ class Wrap extends MultiChildRenderObjectWidget {
 ///    children.
 ///  * The [catalog of layout widgets](https://flutter.dev/widgets/layout/).
 ///
+///
+/// {@animation 450 100 https://flutter.github.io/assets-for-api-docs/assets/widgets/flow_menu.mp4}
+///
 /// {@tool snippet --template=freeform}
 ///
 /// This example uses the [Flow] widget to create a menu that opens and closes
-/// as it is interacted with. The color of the button in the menu changes to
-/// indicate which one has been selected.
-///
-/// {@animation 450 100 https://flutter.github.io/assets-for-api-docs/assets/widgets/flow_menu.mp4}
+/// as it is interacted with, shown above. The color of the button in the menu
+/// changes to indicate which one has been selected.
 ///
 /// ```dart main
 /// import 'package:flutter/material.dart';

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

@@ -16,7 +16,7 @@ import 'will_pop_scope.dart';
 /// with a context whose ancestor is the [Form], or pass a [GlobalKey] to the
 /// [Form] constructor and call [GlobalKey.currentState].
 ///
-/// {@tool snippet --template=stateful_widget_material}
+/// {@tool snippet --template=stateful_widget_scaffold}
 /// This example shows a [Form] with one [TextFormField] and a [RaisedButton]. A
 /// [GlobalKey] is used here to identify the [Form] and validate input.
 ///