refactor: Added and applied require_trailing_commas linter rule

test/command_hint_test.dart

@@ -15,8 +15,11 @@ void main() async {
     final commands = (await prepareTestClient()).commands.keys;
     final missing = commands.where((c) => !translated.contains(c)).toList();
 
-    expect(0, missing.length,
-        reason:
-            'missing hints for $missing\nAdding hints? See scripts/generate_command_hints_glue.sh');
+    expect(
+      0,
+      missing.length,
+      reason:
+          'missing hints for $missing\nAdding hints? See scripts/generate_command_hints_glue.sh',
+    );
   });
 }