minor #987 Update index.rst : adding svelte to regex (youassi)

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

Discussion
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Update index.rst : adding svelte to regex

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| Tickets       | fix doc : adding svelte to regex
| License       | MIT

Commits
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3683425 Update index.rst : adding svelte to regex

Author: weaverryan

src/Svelte/doc/index.rst

@@ -60,7 +60,7 @@ code to your ``assets/app.js`` file:
     // assets/app.js
     import { registerSvelteControllerComponents } from '@symfony/ux-svelte';
 
-    registerSvelteControllerComponents(require.context('./svelte/controllers', true, /\\.(j|t)sx?$/));
+    registerSvelteControllerComponents(require.context('./svelte/controllers', true, /\.svelte$/));
 
 This will load all Svelte components located in the ``assets/svelte/controllers``
 directory. These are known as **Svelte controller components**: top-level