[Doc] Improve tutorial screencast

docs/ReferenceOneInput.md

@@ -240,6 +240,7 @@ Name of the field carrying the relationship on the referenced resource. For inst
 
 In this example, the `<TextInput>` component is wrapped inside a `<MyCustomInput>` component. That adds an icon and additional styling.
 
+{% raw %}
 ```tsx
 import AccountCircle from '@mui/icons-material/AccountCircle';
 import AutoStoriesIcon from '@mui/icons-material/AutoStories';
@@ -279,6 +280,7 @@ export const CustomInputs = () => (
     </ReferenceOneInput>
 );
 ```
+{% endraw %}
 
 ![ReferenceOneInput with custom inputs](https://marmelab.com/ra-enterprise/modules/assets/ra-relationships/latest/reference-one-input-custom-inputs.png)
 

docs/Tutorial.md

@@ -9,8 +9,7 @@ This 30 minutes tutorial will expose how to create a new admin app based on an e
 
 Here is an overview of the result:
 
-<video controls autoplay playsinline muted loop>
-  <source src="./img/tutorial_overview.webm" type="video/webm"/>
+<video controls autoplay playsinline muted loop poster="./img/tutorial_overview.png">
   <source src="./img/tutorial_overview.mp4" type="video/mp4"/>
   Your browser does not support the video tag.
 </video>
@@ -874,7 +873,6 @@ The first filter, 'q', takes advantage of a full-text functionality offered by J
   Your browser does not support the video tag.
 </video>
 
-
 Filters are "search-as-you-type", meaning that when the user enters new values in the filter form, the list refreshes (via an API request) immediately.
 
 **Tip**: Note that the `label` property can be used on any input to customize its label.