minor #1100 Update index.rst (andersmateusz)

This PR was merged into the 2.x branch.

Discussion
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Update index.rst

No escape chars in code sample

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

Missing escape chars in code sample

Commits
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80347d8 Update index.rst

Author: weaverryan

src/Turbo/doc/index.rst

@@ -804,7 +804,7 @@ to ``turbo_stream_listen()``:
 
 .. code-block:: html+twig
 
-    <div id="messages" {{ turbo_stream_listen('App\Entity\Book', 'hub2') }}></div>
+    <div id="messages" {{ turbo_stream_listen('App\\Entity\\Book', 'hub2') }}></div>
 
 Registering a Custom Transport
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~