Add full serve CLI reference back to docs (#20978)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

docs/cli/README.md

@@ -1,3 +1,7 @@
+---
+toc_depth: 4
+---
+
 # vLLM CLI Guide
 
 The vllm command-line tool is used to run and manage vLLM models. You can start by viewing the help message with:
@@ -42,6 +46,10 @@ Start the vLLM OpenAI Compatible API server.
     vllm serve --help=page
     ```
 
+### Options
+
+--8<-- "docs/argparse/serve.md"
+
 ## chat
 
 Generate chat completions via the running API server.