Add llms subdir + update README (#145)

* add llms subdir + update README

* nits

* use same pre-commit as mlx

* update readmes a bit

* format

cifar/resnet.py

@@ -6,11 +6,11 @@ There's no BatchNorm is mlx==0.0.4, using LayerNorm instead.
 """
 
 from typing import Any
+
 import mlx.core as mx
 import mlx.nn as nn
 from mlx.utils import tree_flatten
 
-
 __all__ = [
     "ResNet",
     "resnet20",