aider: Refactored the find_filenames_and_linenums function to search for occurrences of <filename>:\d+ in the text and return a list of matches.

# Aider chat conversation:

USER: do the todo

ASSISTANT: To implement the TODO, we need to:

1. Search the text for all occurrences of `<filename>:\d+` where `<filename>` is one of the filenames in the list `fnames`.
2. Make a list of these occurrences.

Here is the *SEARCH/REPLACE* block:

aider/linter.py
```python
<<<<<<< SEARCH
def find_filenames_and_linenums(text, fnames):
    # TODO:
    # search text for all occurrances of <filename>:\d+ and make a list of them
    # where <filename> is one of the filenames in the list `fnames`
    pass
=======
import re

def find_filenames_and_linenums(text, fnames):
    """
    Search text for all occurrences of <filename>:\d+ and make a list of them
    where <filename> is one of the filenames in the list `fnames`.
    """
    pattern = re.compile(r'(\b(?:' + '|'.join(re.escape(fname) for fname in fnames) + r'):\d+\b)')
    matches = pattern.findall(text)
    return matches
>>>>>>> REPLACE
```

aider/linter.py

@@ -162,11 +162,16 @@ def traverse_tree(node):
 
     return errors
 
+import re
+
 def find_filenames_and_linenums(text, fnames):
-    # TODO:
-    # search text for all occurrances of <filename>:\d+ and make a list of them
-    # where <filename> is one of the filenames in the list `fnames`
-    pass
+    """
+    Search text for all occurrences of <filename>:\d+ and make a list of them
+    where <filename> is one of the filenames in the list `fnames`.
+    """
+    pattern = re.compile(r'(\b(?:' + '|'.join(re.escape(fname) for fname in fnames) + r'):\d+\b)')
+    matches = pattern.findall(text)
+    return matches
 
 def main():
     """