opt.: app bar

Fixes #727

lib/view/page/snippet/edit.dart

@@ -38,7 +38,7 @@ class _SnippetEditPageState extends State<SnippetEditPage>
   @override
   Widget build(BuildContext context) {
     return Scaffold(
-      appBar: AppBar(
+      appBar: CustomAppBar(
         title: Text(libL10n.edit),
         actions: _buildAppBarActions(),
       ),

lib/view/page/snippet/result.dart

@@ -11,7 +11,7 @@ class SnippetResultPage extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return Scaffold(
-      appBar: AppBar(title: Text(l10n.result)),
+      appBar: CustomAppBar(title: Text(l10n.result)),
       body: _buildBody(),
     );
   }