minor #292 Update index.rst (Ldiro)

This PR was merged into the 2.x branch.

Discussion
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Update index.rst

The section "Backward Compatibility promise" is written twice

| Q             | A
| ------------- | ---
| Bug fix?      | yes/no
| New feature?  | yes/no <!-- please update src/**/CHANGELOG.md files -->
| Tickets       | Fix #... <!-- prefix each issue number with "Fix #", no need to create an issue if none exist, explain below instead -->
| License       | MIT

<!--
Replace this notice by a short README for your feature/bugfix. This will help people
understand your PR and can be used as a start for the documentation.

Additionally (see https://symfony.com/releases):
 - Always add tests and ensure they pass.
 - Never break backward compatibility (see https://symfony.com/bc).
 - Features and deprecations must be submitted against branch main.
-->

Commits
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aafce95 Update index.rst

Author: weaverryan

src/Turbo/Resources/doc/index.rst

@@ -785,16 +785,6 @@ Credits
 Symfony UX Turbo has been created by `Kévin Dunglas`_. It has been inspired by
 `hotwired/turbo-rails`_ and `sroze/live-twig`_.
 
-Backward Compatibility promise
-------------------------------
-
-This bundle aims at following the same Backward Compatibility promise as
-the Symfony framework:
-https://symfony.com/doc/current/contributing/code/bc.html
-
-However it is currently considered `experimental`_,
-meaning it is not bound to Symfony's BC policy for the moment.
-
 .. _`Hotwire Turbo`: https://turbo.hotwired.dev
 .. _`the Symfony UX initiative`: https://symfony.com/ux
 .. _`Single Page Apps`: https://en.wikipedia.org/wiki/Single-page_application