minor #18322 [FormCollection] mention Symfony UX live collection (94noni)

This PR was submitted for the 6.2 branch but it was merged into the 5.4 branch instead.

Discussion
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[FormCollection] mention Symfony UX live collection

Commits
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6f74096 [FormCollection] mention Symfony UX live collection

Author: javiereguiluz

form/form_collections.rst

@@ -213,6 +213,11 @@ Previously you added two tags to your task in the controller. Now let the users
 add as many tag forms as they need directly in the browser. This requires a bit
 of JavaScript code.
 
+.. tip::
+
+    You can leverage Symfony UX via https://ux.symfony.com/live-component/demos/form-collection-type
+    if you do not want to handle the JavaScript code yourself.
+
 But first, you need to let the form collection know that instead of exactly two,
 it will receive an *unknown* number of tags. Otherwise, you'll see a
 *"This form should not contain extra fields"* error. This is done with the