minor #3127 added missing import to code snippet (rgeraads)

This PR was merged into the 2.x branch.

Discussion
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 added missing import to code snippet

| Q              | A
| -------------- | ---
| Bug fix?       | no
| New feature?   | no <!-- please update src/**/CHANGELOG.md files -->
| Deprecations?  | no <!-- if yes, also update UPGRADE-*.md and src/**/CHANGELOG.md -->
| Documentation? | yes <!-- required for new features, or documentation updates -->
| Issues         | Fix #... <!-- prefix each issue number with "Fix #", no need to create an issue if none exist, explain below instead -->
| License        | MIT

Commits
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09ca471 added missing import to code snippet

Author: Kocal

src/LiveComponent/doc/index.rst

@@ -948,6 +948,7 @@ component system from Stimulus:
 
     // assets/controllers/some-custom-controller.js
     // ...
+    import { Controller } from '@hotwired/stimulus';
     import { getComponent } from '@symfony/ux-live-component';
 
     export default class extends Controller {