Add missing docs explaining ignore

Author: daohoangson

demo_app/integration_test/auto_resize_test.dart

@@ -24,10 +24,10 @@ void main() {
   });
 
   final webViewTestCases = ValueVariant(const {
-    WebViewTestCase(0.5, false),
-    WebViewTestCase(1.0, false),
-    WebViewTestCase(2.0, false),
-    WebViewTestCase(1.0, true),
+    WebViewTestCase(input: 0.5, issue375: false),
+    WebViewTestCase(input: 1.0, issue375: false),
+    WebViewTestCase(input: 2.0, issue375: false),
+    WebViewTestCase(input: 1.0, issue375: true),
   });
 
   patrolTest(
@@ -64,8 +64,10 @@ class WebViewTestCase {
   final double input;
   final bool issue375;
 
-  // ignore: avoid_positional_boolean_parameters
-  const WebViewTestCase(this.input, this.issue375);
+  const WebViewTestCase({
+    required this.input,
+    required this.issue375,
+  });
 
   Future<_AspectRatioTest> run(PatrolIntegrationTester $) async {
     final html = '''

packages/core/lib/src/core_legacy.dart

@@ -1,3 +1,4 @@
+// intentionally uses deprecated members for backwards compatibility
 // ignore_for_file: deprecated_member_use_from_same_package
 
 import 'package:flutter/widgets.dart';

packages/core/lib/src/internal/core_build_tree.dart

@@ -450,6 +450,7 @@ class _LockableDeclarations extends LockableList<css.Declaration> {
 
 class _WidgetPlaceholderDefault extends StatelessWidget
     implements
+        // internal implementation detail of our own placeholder
         // ignore: avoid_implementing_value_types
         WidgetPlaceholder {
   const _WidgetPlaceholderDefault();