minor #9015 Update URLs for Symfony4 (weaverryan)

This PR was merged into the 4.0 branch.

Discussion
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Update URLs for Symfony4

Just updating a few URLs & description for the Sf4 course on KnpU :). The linked setup chapter will be published momentarily...

Commits
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298ceab Updating KnpU URLs for Symfony 4

Author: weaverryan

page_creation.rst

@@ -20,7 +20,7 @@ simple two-step process:
 
 .. seealso::
 
-    Do you prefer video tutorials? Check out the `Joyful Development with Symfony`_
+    Do you prefer video tutorials? Check out the `Stellar Development with Symfony`_
     screencast series from KnpUniversity.
 
 .. seealso::
@@ -341,5 +341,5 @@ Go Deeper with HTTP & Framework Fundamentals
 
 .. _`Twig`: http://twig.sensiolabs.org
 .. _`Composer`: https://getcomposer.org
-.. _`Joyful Development with Symfony`: http://knpuniversity.com/screencast/symfony/first-page
+.. _`Stellar Development with Symfony`: https://knpuniversity.com/screencast/symfony/setup
 .. _`symfony.sh`: https://symfony.sh/

setup.rst

@@ -6,7 +6,7 @@ Installing & Setting up the Symfony Framework
 
 .. seealso::
 
-    Do you prefer video tutorials? Check out the `Joyful Development with Symfony`_
+    Do you prefer video tutorials? Check out the `Stellar Development with Symfony`_
     screencast series from KnpUniversity.
 
 To create your new Symfony application, first make sure you're using PHP 7.1 or higher
@@ -150,7 +150,7 @@ Go Deeper with Setup
     setup/composer
     setup/*
 
-.. _`Joyful Development with Symfony`: http://knpuniversity.com/screencast/symfony
+.. _`Stellar Development with Symfony`: http://knpuniversity.com/screencast/symfony
 .. _`Composer`: https://getcomposer.org/
 .. _`technical requirements`: https://symfony.com/doc/current/reference/requirements.html
 .. _`The Symfony Demo application`: https://github.com/symfony/symfony-demo