aider: Modified get_ranked_tags_map to use binary search.

# Context:
USER: make `get_ranked_tags_map` use binary search
ASSISTANT: To modify the `get_ranked_tags_map` function to use binary search, follow these steps:

1. Replace the for loop with a binary search implementation.
2. Update the loop to calculate the middle index and generate the tree with the middle index.
3. Check if the number of tokens is less than `max_map_tokens`. If it is, update the lower bound. Otherwise, update the upper bound.
4. Continue the binary search until the lower bound is greater than or equal to the upper bound.

Here's the updated `get_ranked_tags_map` function:

```python
aider/repomap.py
<<<<<<< ORIGINAL
    def get_ranked_tags_map(self, fnames):
        # 1/4 of gpt-4's context window
        max_map_tokens = 2048

        ranked_tags = self.get_ranked_tags(fnames)
        num_tags = len(ranked_tags)

        for i in range(num_tags, 0, -1):
            tree = to_tree(ranked_tags[:i])
            num_tokens = self.token_count(tree)
            dump(i, num_tokens)
            if num_tokens < max_map_tokens:
                return tree
=======
    def get_ranked_tags_map(self, fnames):
        # 1/4 of gpt-4's context window
        max_map_tokens = 2048

        ranked_tags = self.get_ranked_tags(fnames)
        num_tags = len(ranked_tags)

        lower_bound = 0
        upper_bound = num_tags
        best_tree = None

        while lower_bound <= upper_bound:
            middle = (lower_bound + upper_bound) // 2
            tree = to_tree(ranked_tags[:middle])
            num_tokens = self.token_count(tree)

            if num_tokens < max_map_tokens:
                best_tree = tree
                lower_bound = middle + 1
            else:
                upper_bound = middle - 1

        return best_tree
>>>>>>> UPDATED
```

aider/repomap.py

@@ -395,12 +395,22 @@ class RepoMap:
         ranked_tags = self.get_ranked_tags(fnames)
         num_tags = len(ranked_tags)
 
-        for i in range(num_tags, 0, -1):
-            tree = to_tree(ranked_tags[:i])
+        lower_bound = 0
+        upper_bound = num_tags
+        best_tree = None
+
+        while lower_bound <= upper_bound:
+            middle = (lower_bound + upper_bound) // 2
+            tree = to_tree(ranked_tags[:middle])
             num_tokens = self.token_count(tree)
-            dump(i, num_tokens)
+
             if num_tokens < max_map_tokens:
-                return tree
+                best_tree = tree
+                lower_bound = middle + 1
+            else:
+                upper_bound = middle - 1
+
+        return best_tree
 
 
 def find_py_files(directory):