Documentation fix for subresource custom path.

I was having problems with adding custom path name for subresource operation. I've followed suggestions from [this comment](api-platform/api-platform#1581 (comment)) and it worked fine, so I am proposing a change to the documentation.

Author: piotrgradzinski

core/subresources.md

@@ -178,15 +178,15 @@ may use `bin/console debug:router`.
 
 ## Using Custom Paths
 
-You can control the path of subresources with the `path` option of the `subresourceOperations` parameter:
+You can control the path of subresources with the `path` option of the `subresourceOperations` parameter. Notice that you don't have to use the prefix `api_questions_` because it's an operation name:
 
 ```php
 <?php
 // api/src/Entity/Question.php
 
 #[ApiResource(
     subresourceOperations: [
-        'api_questions_answer_get_subresource' => [
+        'answer_get_subresource' => [
             'method' => 'GET',
             'path' => '/questions/{id}/all-answers',
         ],