minor #1136 Fix some code block styles & lost code block in docs (bocharsky-bw)

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

Discussion
----------

Fix some code block styles & lost code block in docs

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

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<img width="878" alt="Screenshot 2023-09-22 at 17 06 21" src="https://github.com/symfony/ux/assets/3317635/1308a5e4-30b3-4532-b3f8-1f34129c8111">

Commits
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05ae6d0 Fix some code block styles & lost code block in docs

Author: weaverryan

src/LiveComponent/doc/index.rst

@@ -3100,17 +3100,12 @@ Add a Hook on LiveProp Update
 
 If you want to run custom code after a specific LiveProp is updated,
 you can do it by adding an ``onUpdated`` option set to a public method name
-on the component:
-
-.. code-block:: diff
-
-    // ...
+on the component::
 
     #[AsLiveComponent]
     class ProductSearch
     {
-      - #[LiveProp(writable: true)]
-      + #[LiveProp(writable: true, onUpdated: 'onQueryUpdated')]
+        #[LiveProp(writable: true, onUpdated: 'onQueryUpdated')]
         public string $query = '';
 
         // ...
@@ -3121,17 +3116,14 @@ on the component:
             // and its previous value is passed as an argument
         }
     }
-}
 
-As soon as the `query` LiveProp is updated, the ``onQueryUpdated()`` method
+As soon as the ``query`` LiveProp is updated, the ``onQueryUpdated()`` method
 will be called. The previous value is passed there as the first argument.
 
 If you're allowing object properties to be writable, you can also listen to
-the change of one specific key:
+the change of one specific key::
 
-.. code-block::
-
-    // ...
+    use App\Entity\Post;
 
     #[AsLiveComponent]
     class EditPost