[ios_platform_images] Adopt code-excerpts (#5682)

Replaces the Dart example code with a code excerpt.

Part of https://github.com/flutter/flutter/issues/102679

packages/ios_platform_images/CHANGELOG.md

@@ -1,5 +1,6 @@
-## NEXT
+## 0.2.3+1
 
+* Improves example code in README.
 * Updates minimum supported SDK version to Flutter 3.10/Dart 3.0.
 
 ## 0.2.3

packages/ios_platform_images/README.md

@@ -16,20 +16,13 @@ When loading images from Image.xcassets the device specific variant is chosen
 
 ### iOS->Flutter Example
 
-``` dart
-// Import package
-import 'package:ios_platform_images/ios_platform_images.dart';
-
-Widget build(BuildContext context) {
-  return MaterialApp(
-    home: Scaffold(
-      body: Center(
-        child: Image(image: IosPlatformImages.load("flutter")),
-      ),
-      //..
-    ),
-  );
-}
+<?code-excerpt "example/lib/main.dart (Usage)"?>
+```dart
+// "flutter" is a resource in Assets.xcassets.
+final Image xcassetImage = Image(
+  image: IosPlatformImages.load('flutter'),
+  semanticLabel: 'Flutter logo',
+);
 ```
 
 `IosPlatformImages.load` works similarly to [`UIImage(named:)`](https://developer.apple.com/documentation/uikit/uiimage/1624146-imagenamed).

packages/ios_platform_images/example/lib/main.dart

@@ -28,17 +28,20 @@ class _MyAppState extends State<MyApp> {
 
   @override
   Widget build(BuildContext context) {
+    // #docregion Usage
+    // "flutter" is a resource in Assets.xcassets.
+    final Image xcassetImage = Image(
+      image: IosPlatformImages.load('flutter'),
+      semanticLabel: 'Flutter logo',
+    );
+    // #enddocregion Usage
     return MaterialApp(
       home: Scaffold(
         appBar: AppBar(
           title: const Text('Plugin example app'),
         ),
         body: Center(
-          // "flutter" is a resource in Assets.xcassets.
-          child: Image(
-            image: IosPlatformImages.load('flutter'),
-            semanticLabel: 'Flutter logo',
-          ),
+          child: xcassetImage,
         ),
       ),
     );

packages/ios_platform_images/pubspec.yaml

@@ -2,7 +2,7 @@ name: ios_platform_images
 description: A plugin to share images between Flutter and iOS in add-to-app setups.
 repository: https://github.com/flutter/packages/tree/main/packages/ios_platform_images
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+ios_platform_images%22
-version: 0.2.3
+version: 0.2.3+1
 
 environment:
   sdk: ">=3.0.0 <4.0.0"

script/configs/temp_exclude_excerpt.yaml

@@ -10,7 +10,6 @@
 - go_router_builder
 - image_picker_for_web
 - in_app_purchase/in_app_purchase
-- ios_platform_images
 - palette_generator
 - pointer_interceptor
 - quick_actions/quick_actions