aider: Changed cmd_run method to intermingle stdout and stderr using subprocess.PIPE for both and setting stderr=subprocess.STDOUT.

# Context:
USER: rather than concatenating stdin and stderr, can we get them intermingled like they would be shown in normal terminal output
ASSISTANT: Yes, you can intermingle stdout and stderr like they would be shown in normal terminal output by using the `subprocess.PIPE` for both stdout and stderr, and setting `stderr=subprocess.STDOUT`. We will modify the `cmd_run` method in the `aider/commands.py` file to implement this change.

Here are the changes to `aider/commands.py`:

```python
aider/commands.py
<<<<<<< ORIGINAL
231             parsed_args = shlex.split(args)
232             result = subprocess.run(parsed_args, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True)
233             combined_output = result.stdout + result.stderr
=======
231             parsed_args = shlex.split(args)
232             result = subprocess.run(parsed_args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, text=True)
233             combined_output = result.stdout
>>>>>>> UPDATED
```

These changes set `stderr=subprocess.STDOUT` in the `subprocess.run()` call, which will intermingle stdout and stderr like they would be shown in normal terminal output.

aider/commands.py

@@ -230,8 +230,8 @@ class Commands:
 229         "Run the supplied command in a subprocess and combine stdout and stderr into a single string"
 230         try:
 231             parsed_args = shlex.split(args)
-232             result = subprocess.run(parsed_args, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True)
-232             combined_output = result.stdout + result.stderr
+232             result = subprocess.run(parsed_args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, text=True)
+233             combined_output = result.stdout
 233             print(combined_output)
 234         except Exception as e:
 235             self.io.tool_error(f"Error running command: {e}")