feat(i18n)!: rename few files + add clearer documentation

packages/wyatt_i18n/example/lib/main.dart

@@ -29,36 +29,32 @@ class App extends StatelessWidget {
   static const String title = 'Wyatt i18n Example';
 
   @override
-  Widget build(BuildContext context) {
-    final I18nDataSource dataSource = NetworkDataSourceImpl(
-      baseUri: Uri.parse(
-        'https://git.wyatt-studio.fr/Wyatt-FOSS/wyatt-packages/raw/commit/75f561a19e0484e67e511dbf29601ec5f58544aa/packages/wyatt_i18n/example/assets/',
-      ),
-    );
-
-    final I18nRepository repository =
-        I18nRepositoryImpl(dataSource: dataSource);
-
-    return MaterialApp(
-      title: title,
-      theme: ThemeData(
-        primarySwatch: Colors.blue,
-      ),
-      localizationsDelegates: [
-        I18nDelegate(repository: repository),
-        GlobalMaterialLocalizations.delegate,
-        GlobalWidgetsLocalizations.delegate
-      ],
-      home: Scaffold(
-        appBar: AppBar(
-          title: const Text(title),
+  Widget build(BuildContext context) => MaterialApp(
+        title: title,
+        theme: ThemeData(
+          primarySwatch: Colors.blue,
         ),
-        body: Builder(
-          builder: (ctx) => Center(
-            child: Text(ctx.i18n('youHavePushed', {'count': 654})),
+        localizationsDelegates: [
+          I18nDelegate(
+            dataSource: NetworkI18nDataSourceImpl(
+              baseUri: Uri.parse(
+                'https://git.wyatt-studio.fr/Wyatt-FOSS/wyatt-packages/raw/commit/75f561a19e0484e67e511dbf29601ec5f58544aa/packages/wyatt_i18n/example/assets/',
+              ),
+              localeTransformer: (locale) => locale.languageCode,
+            ),
+          ),
+          GlobalMaterialLocalizations.delegate,
+          GlobalWidgetsLocalizations.delegate
+        ],
+        home: Scaffold(
+          appBar: AppBar(
+            title: const Text(title),
+          ),
+          body: Builder(
+            builder: (ctx) => Center(
+              child: Text(ctx.i18n('youHavePushed', {'count': 654})),
+            ),
           ),
         ),
-      ),
-    );
-  }
+      );
 }