style: Run linter and fix whitespace issues in models.py and sendchat.py

aider/models.py

@@ -552,6 +552,7 @@ class Model(ModelSettings):
         # dump(kwargs)
         hash_object = hashlib.sha1(key)
         from aider.sendchat import litellm
+
         res = litellm.completion(**kwargs)
         return hash_object, res
 

aider/sendchat.py

@@ -1,7 +1,6 @@
 from aider.dump import dump  # noqa: F401
 from aider.utils import format_messages
 
-
 RETRY_TIMEOUT = 60