fix nits

Author: mansourzaki

packages/flutter/lib/src/material/banner.dart

@@ -157,7 +157,7 @@ class MaterialBanner extends StatefulWidget {
   /// Typically an [Icon] widget.
   final Widget? leading;
 
-  /// The (optional) minActionBarHeight allows users to set minimum action bar height.
+  /// The optional minimum action bar height.
   ///
   /// Default is 52.0.
   final double minActionBarHeight;

packages/flutter/test/material/banner_test.dart

@@ -1175,7 +1175,7 @@ void main() {
     expect(size.height, equals(minActionBarHeight));
   });
 
-   testWidgets('MinimumActionBarHeight respected with ScaffolMessenger', (WidgetTester tester) async {
+   testWidgets('MinimumActionBarHeight respects with ScaffoldMessenger', (WidgetTester tester) async {
     const Key tapTarget = Key('tap-target');
     const double minActionBarHeight = 20;
     await tester.pumpWidget(MaterialApp(