refactor(comments): rename test file to match implementation

Rename test_watch.py to test_comment_processor.py to match the renamed
implementation class and better reflect its testing scope. Updates imports
and class references accordingly.

tests/basic/test_watch.py → tests/basic/test_comment_processor.py

@@ -1,7 +1,7 @@
 from pathlib import Path
 
 from aider.io import InputOutput
-from aider.watch import FileWatcher
+from aider.comment_processor import CommentProcessor
 
 
 def test_gitignore_patterns():
@@ -74,7 +74,7 @@ def get_rel_fname(self, fname):
 
     io = InputOutput(pretty=False, fancy_input=False, yes=False)
     coder = MinimalCoder(io)
-    watcher = FileWatcher(coder)
+    watcher = CommentProcessor(io, coder)
     fixtures_dir = Path(__file__).parent.parent / "fixtures"
 
     # Test Python fixture