fix typo

Author: mrdbourke

00_pytorch_fundamentals.ipynb

@@ -1463,6 +1463,7 @@
     "PyTorch implements matrix multiplication functionality in the [`torch.matmul()`](https://pytorch.org/docs/stable/generated/torch.matmul.html) method.\n",
     "\n",
     "The main two rules for matrix multiplication to remember are:\n",
+    "\n",
     "1. The **inner dimensions** must match:\n",
     "  * `(3, 2) @ (3, 2)` won't work\n",
     "  * `(2, 3) @ (3, 2)` will work\n",