minor #16116 Update page_creation.rst (94noni)

This PR was submitted for the 5.4 branch but it was merged into the 5.3 branch instead.

Discussion
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Update page_creation.rst

Code snippet before (`Creating a Page: Route and Controller`) and after (`Rendering a Template`)
of this controller exemple have this return, I think it is missed here, wdyt?

Commits
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2075bb9 Update page_creation.rst

Author: javiereguiluz

page_creation.rst

@@ -118,7 +118,7 @@ You can now add your route directly *above* the controller:
         +   /**
         +    * @Route("/lucky/number")
         +    */
-            public function number()
+            public function number(): Response
             {
                 // this looks exactly the same
             }
@@ -134,7 +134,7 @@ You can now add your route directly *above* the controller:
         class LuckyController
         {
         +   #[Route('/lucky/number')]
-            public function number()
+            public function number(): Response
             {
                 // this looks exactly the same
             }