Possible typo in week1-01-attention (#60)

* Possible typo in week1-01-attention

Hello, was going through the book! I'm not 100% sure of this, but after going through the tests for day1-task2, it looks like the w_qkv matrices and w_o matrix have their shape reversed.

I confirmed by checking the mlx.nn.layers.linear.Linear weight, which is of shape `[Output, Input]`. Since w_qkv's output is HxD and input is E, the shape should be `[H x D, E]`.

* Oops fix another typo

Author: ekzhang

book/src/week1-01-attention.md

@@ -118,9 +118,9 @@ H is num_heads
 D is head_dim
 L is seq_len, in PyTorch API it's S (source len)
 
-w_q/w_k/w_v: E x (H x D)
+w_q/w_k/w_v: (H x D) x E
 output/input: N x L x E
-w_o: (H x D) x E
+w_o: E x (H x D)
 ```
 
 At the end of the task, you should be able to pass the following tests: