Fix broken links in PHP roadmap (#8624)

* Update csrf-protection@J9yIXZTtwbFzH2u4dI1ep.md

Fix broken link

* Update inheritance@c5q2e_jyMt8Pir5Od3lRi.md

Fix broken link

* Update polymorphism@gtq5KrghF28f5G8nuDcYQ.md

Fix broken link

src/data/roadmaps/php/content/csrf-protection@J9yIXZTtwbFzH2u4dI1ep.md

@@ -18,4 +18,4 @@ if(isset($_POST['csrf']) && $_POST['csrf'] === $_SESSION['csrf']) {
 
 Visit the following resources to learn more:
 
-- [@article@PHP Tutorial CSRF] (https://www.phptutorial.net/php-tutorial/php-csrf/)
+- [@article@PHP Tutorial CSRF](https://www.phptutorial.net/php-tutorial/php-csrf/)

src/data/roadmaps/php/content/inheritance@c5q2e_jyMt8Pir5Od3lRi.md

@@ -25,4 +25,4 @@ In the above example, the 'Car' class inherits the drive method from the 'Vehicl
 
 Visit the following resources to learn more:
 
-- [@official@Inheritance](https://www.php.net/manual/en/keyword.extends.php)
+- [@official@Inheritance](https://www.php.net/manual/en/language.oop5.inheritance.php)

src/data/roadmaps/php/content/polymorphism@gtq5KrghF28f5G8nuDcYQ.md

@@ -35,4 +35,4 @@ This creates a scalable way to add more shapes, as you only need to follow the '
 
 Visit the following resources to learn more:
 
-- [@official@Polymorphism](https://www.php.net/manual/en/language.oop5.polymorphism.php)
+- [@opensource@Polymorphism](https://www.phptutorial.net/php-oop/php-polymorphism/)