aider: Fixed IO class initialization in test_cmd_add.

# Context:
USER: I ran this command:

 pytest tests/test_commands.py

Which produced this output:

============================= test session starts ==============================
platform darwin -- Python 3.11.3, pytest-7.3.1, pluggy-1.0.0
rootdir: /Users/gauthier/Projects/aider
collected 1 item

tests/test_commands.py F                                                 [100%]

=================================== FAILURES ===================================
__________________________ TestCommands.test_cmd_add ___________________________

self = <tests.test_commands.TestCommands testMethod=test_cmd_add>

    def test_cmd_add(self):
        with tempfile.TemporaryDirectory() as tmpdir:
>           io = IO()
E           TypeError: InputOutput.__init__() missing 4 required positional arguments: 'pretty', 'yes', 'input_history_file', and 'chat_history_file'

tests/test_commands.py:12: TypeError
=========================== short test summary info ============================
FAILED tests/test_commands.py::TestCommands::test_cmd_add - TypeError: InputO...
============================== 1 failed in 0.47s ===============================

ASSISTANT: I apologize for the oversight. The `InputOutput` class requires four arguments during initialization. Let's update the test to provide the required arguments.

```python
tests/test_commands.py
<<<<<<< ORIGINAL
io = IO()
=======
io = IO(pretty=False, yes=True, input_history_file=None, chat_history_file=None)
>>>>>>> UPDATED
```

This change should fix the `TypeError` when initializing the `IO` class in the test.

tests/test_commands.py

@@ -9,7 +9,7 @@ from aider.coder import Coder
 class TestCommands(unittest.TestCase):
     def test_cmd_add(self):
         with tempfile.TemporaryDirectory() as tmpdir:
-            io = IO()
+            io = IO(pretty=False, yes=True, input_history_file=None, chat_history_file=None)
             coder = Coder(root=tmpdir)
             commands = Commands(io, coder)