docs: update docs

Author: pbastia

docs/file_uploads.md

@@ -48,14 +48,18 @@ const ComponentWithForm = (props) => {
 
   return <Form
     schema={schema}
-    formContext={...fileWidgetContext}
+    formContext={{...otherContext, ...fileWidgetContext}
     onSubmit={handleSubmit}
   />
 
 }
 
 ```
 
+> [!NOTE]
+> The `FileWidget` sets the string value to a serialized JSON string: '{"status": "Clean", "name": "FileName.pdf", "id": 1234}'
+> The backend is expected to follow that schema when passing form data
+
 ### Backend considerations
 
 - The payload will contain a serialized `{id: <id | undefined>, name: <name>, status: <"unscanned"|"clean"|...>}` object that will be part of the form data. Parsing that form data on the backend can be useful