minor #1672 [Website] Fix some links in the UX Icons page (javiereguiluz)

This PR was squashed before being merged into the 2.x branch.

Discussion
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[Website] Fix some links in the UX Icons page

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| Issues        | -
| License       | MIT

`@tareqas` found and reported these errors to me ... so let's fix them!

Commits
-------

8a11646 [Website] Fix some links in the UX Icons page

Author: javiereguiluz

ux.symfony.com/templates/icons/_aside.html.twig

@@ -4,13 +4,13 @@
             <twig:DocsLink
                 title="Documentation"
                 text="Get going with the official Symfony doc."
-                url="https://www.symfony.com/doc/ux.html"
+                url="https://symfony.com/bundles/ux-icons/current/index.html"
                 icon="symfony"
             />
             <twig:DocsLink
                 title="Screencasts"
-                text="Watch the screencast on SymfonyCasts."
-                url="https://symfonycasts.com/screencast/symfony-ux"
+                text="Watch UX screencasts on SymfonyCasts."
+                url="https://symfonycasts.com/screencast/stimulus"
                 icon="symfonycast"
             />
             <twig:DocsLink