Update CUDA-ExecutionProvider.md to add TOC (#20443)

### Description
CUDA-ExecutionProvider.md table of contents previously not showing up
correctly b/c of spacing issue.



### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->

docs/execution-providers/CUDA-ExecutionProvider.md

@@ -13,11 +13,10 @@ redirect_from: /docs/reference/execution-providers/CUDA-ExecutionProvider
 The CUDA Execution Provider enables hardware accelerated computation on Nvidia CUDA-enabled GPUs.
 
 ## Contents
-
 {: .no_toc }
 
 * TOC placeholder
-  {:toc}
+{:toc}
 
 ## Install