aider: Replaced redirect_stdout with redirect_stdin and opened os.devnull in read mode ('r') instead of write mode ('w').

# Context:
USER: stdin not stdout
ASSISTANT: I apologize for the confusion. To redirect stdin instead of stdout, we need to use `contextlib.redirect_stdin` instead of `contextlib.redirect_stdout`. Here's the updated code change for tests/test_main.py:

```python
tests/test_main.py
<<<<<<< ORIGINAL
    with open(os.devnull, 'w') as dev_null:
        with redirect_stdout(dev_null):
=======
    with open(os.devnull, 'r') as dev_null:
        with redirect_stdin(dev_null):
>>>>>>> UPDATED
            main()
```

This code change replaces `redirect_stdout` with `redirect_stdin` and opens os.devnull in read mode ('r') instead of write mode ('w').

tests/test_main.py

@@ -9,6 +9,6 @@ class TestMain(TestCase):
     def test_main_with_dev_null(self):
         with tempfile.TemporaryDirectory() as temp_dir:
             os.chdir(temp_dir)
-            with open(os.devnull, 'w') as dev_null:
-                with redirect_stdout(dev_null):
+    with open(os.devnull, 'r') as dev_null:
+        with redirect_stdin(dev_null):
                     main()