minor #17200 Inappropriate usage of Parameter Conversion (githubfromgui)

This PR was merged into the 4.4 branch.

Discussion
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Inappropriate usage of Parameter Conversion

Under the section `Route Groups and Prefixes`, the action `show` seems to make usage of `Parameter Conversion` technique, though there is no reference for the `Post` class in that code snippet.

I would suggest to replace the parameter `Post $post` to `string $slug` , matching the URL parameter defined above the method `show`.

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Commits
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e35ee1a Inappropriate usage of Parameter Conversion

Author: javiereguiluz

routing.rst

@@ -1180,7 +1180,7 @@ the common configuration using options when importing the routes.
             /**
              * @Route("/{_locale}/posts/{slug}", name="show")
              */
-            public function show(Post $post): Response
+            public function show(string $slug): Response
             {
                 // ...
             }