Update L22.md

lectures/flipped/L22.md

@@ -29,7 +29,7 @@ one-dimensional block)
 Answers:
 
 * `x + y Dx` and `x + y Dx + z Dx Dy` (see
-  [here](https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#thread-hierarchy)
+  [here](https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#thread-hierarchy))
 
 * No, they can be executed in any order (see
   [here](https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#scalable-programming-model-automatic-scalability))