migrate docstrings from reST to google format

tests/ahriman/application/handlers/test_handler_add.py

@@ -13,8 +13,12 @@ from ahriman.models.result import Result
 def _default_args(args: argparse.Namespace) -> argparse.Namespace:
     """
     default arguments for these test cases
-    :param args: command line arguments fixture
-    :return: generated arguments for these test cases
+
+    Args:
+      args(argparse.Namespace): command line arguments fixture
+
+    Returns:
+      argparse.Namespace: generated arguments for these test cases
     """
     args.package = []
     args.exit_code = False