[Doc] Fix internal links so they don't always point to latest (#20563)

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

docs/features/structured_outputs.md

@@ -157,7 +157,7 @@ As an example, we can use to define a specific format of simplified SQL queries:
     print(completion.choices[0].message.content)
     ```
 
-See also: [full example](https://docs.vllm.ai/en/latest/examples/online_serving/structured_outputs.html)
+See also: [full example](../examples/online_serving/structured_outputs.md)
 
 ## Reasoning Outputs
 
@@ -200,7 +200,7 @@ Note that you can use reasoning with any provided structured outputs feature. Th
     print("content: ", completion.choices[0].message.content)
     ```
 
-See also: [full example](https://docs.vllm.ai/en/latest/examples/online_serving/structured_outputs.html)
+See also: [full example](../examples/online_serving/structured_outputs.md)
 
 ## Experimental Automatic Parsing (OpenAI API)
 
@@ -325,4 +325,4 @@ shown below:
     print(outputs[0].outputs[0].text)
     ```
 
-See also: [full example](https://docs.vllm.ai/en/latest/examples/online_serving/structured_outputs.html)
+See also: [full example](../examples/online_serving/structured_outputs.md)