Cleanup in gen_l10n files (#54401)

dev/tools/localization/gen_l10n.dart

@@ -875,7 +875,7 @@ class LocalizationsGenerator {
         stdout.writeln('"$locale": ${messages.length} untranslated message(s).');
       });
       stdout.writeln(
-        'To see a detailed report, use the --unimplemented-messages-file \n'
+        'To see a detailed report, use the --untranslated-messages-file \n'
         'option in the tool to generate a JSON format file containing \n'
         'all messages that need to be translated.'
       );

dev/tools/localization/gen_l10n_templates.dart

@@ -10,13 +10,10 @@ import 'dart:async';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_localizations/flutter_localizations.dart';
-// ignore: unused_import
 import 'package:intl/intl.dart' as intl;
 
 @(messageClassImports)
 
-// ignore_for_file: unnecessary_brace_in_string_interps
-
 /// Callers can lookup localized strings with an instance of @(class) returned
 /// by `@(class).of(context)`.
 ///
@@ -44,8 +41,7 @@ import 'package:intl/intl.dart' as intl;
 ///   # Internationalization support.
 ///   flutter_localizations:
 ///     sdk: flutter
-///   intl: 0.16.0
-///   intl_translation: 0.17.7
+///   intl: 0.16.1
 ///
 ///   # rest of dependencies
 /// ```