[Doc] Convert docs to use colon fences (#12471)

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

docs/source/serving/engine_args.md

@@ -4,6 +4,7 @@
 
 Below, you can find an explanation of every engine argument for vLLM:
 
+<!--- pyml disable-num-lines 7 no-space-in-emphasis-->
 ```{eval-rst}
 .. argparse::
     :module: vllm.engine.arg_utils
@@ -16,6 +17,7 @@ Below, you can find an explanation of every engine argument for vLLM:
 
 Below are the additional arguments related to the asynchronous engine:
 
+<!--- pyml disable-num-lines 7 no-space-in-emphasis-->
 ```{eval-rst}
 .. argparse::
     :module: vllm.engine.arg_utils