aider: Changed self.words initialization from an empty list to an empty set and replaced the extend method with the update method to add words to the set.

# Context:
USER: self.words should be a set not a list
ASSISTANT: To change `self.words` from a list to a set, we will update the `__init__` method in the `FileContentCompleter` class. Here's the updated code:

```python
aider/getinput.py
<<<<<<< ORIGINAL
class FileContentCompleter(Completer):
    def __init__(self, fnames):
        self.words = []
        for fname in fnames:
            with open(fname, "r") as f:
                content = f.read()
            self.words.extend(re.split(r'\W+', content))
=======
class FileContentCompleter(Completer):
    def __init__(self, fnames):
        self.words = set()
        for fname in fnames:
            with open(fname, "r") as f:
                content = f.read()
            self.words.update(re.split(r'\W+', content))
>>>>>>> UPDATED
```

This change updates the `self.words` initialization from an empty list to an empty set and replaces the `extend` method with the `update` method to add words to the set.

aider/getinput.py

@@ -27,12 +27,11 @@ class Commands:
 
 class FileContentCompleter(Completer):
     def __init__(self, fnames):
-        self.words = []
+        self.words = set()
         for fname in fnames:
             with open(fname, "r") as f:
                 content = f.read()
-            self.words.extend(re.split(r'\W+', content))
+            self.words.update(re.split(r'\W+', content))
-
     def get_completions(self, document, complete_event):
         text = document.text_before_cursor
         words = text.split()